SwipeRefreshLayout, refresh in background thread

Last post show a basic example of SwipeRefreshLayout. But, normally refreshing involve some longtime task; such as loading data from Internet. This example show how to refresh with longtime task in background thread.


MainActivity.java

package com.blogspot.android_er.androidswiperefresh;

import android.os.Bundle;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toast;

import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    SwipeRefreshLayout swipeRefreshLayout;
    ListView swipeList;

    List<String> myList;
    ListAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        swipeRefreshLayout = (SwipeRefreshLayout)findViewById(R.id.swiperefreshlayout);
        swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                refresh();
            }
        });

        swipeList = (ListView)findViewById(R.id.swipelist);

        myList = new ArrayList<>();
        adapter = new ArrayAdapter<String>(
                this, android.R.layout.simple_list_item_1, myList);
        swipeList.setAdapter(adapter);

        swipeList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                String item = (String) parent.getItemAtPosition(position);
                Toast.makeText(MainActivity.this, item, Toast.LENGTH_LONG).show();
            }
        });
    }

    private void refresh(){

        final int pos = myList.size();
        myList.add(pos, "Refreshing...");
        swipeList.invalidateViews();
        swipeRefreshLayout.setRefreshing(true);

        //refresh long-time task in background thread
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    //dummy delay for 2 second
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                //update ui on UI thread
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        String currentDateTime =
                                DateFormat.getDateTimeInstance().format(new Date());
                        myList.set(pos, pos + " - " + currentDateTime);
                        swipeList.invalidateViews();
                        swipeRefreshLayout.setRefreshing(false);
                    }
                });

            }
        }).start();
    }
}

Keep using the layout in last post.

more:
- SwipeRefreshLayout, work with RecyclerView

Swipe-to-Refresh ListView using SwipeRefreshLayout

With android.support.v4.widget.SwipeRefreshLayout, user can refresh the contents of a view via a vertical swipe gesture. This example show how to implement Swipe-to-Refresh ListView using SwipeRefreshLayout.


activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidswiperefresh.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <android.support.v4.widget.SwipeRefreshLayout
        android:id="@+id/swiperefreshlayout"
        android:layout_height="match_parent"
        android:layout_width="match_parent">
        <ListView
            android:id="@+id/swipelist"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    </android.support.v4.widget.SwipeRefreshLayout>

</LinearLayout>

MainActivity.java

package com.blogspot.android_er.androidswiperefresh;

import android.os.Bundle;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;

import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    SwipeRefreshLayout swipeRefreshLayout;
    ListView swipeList;

    List<String> myList;
    ListAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        swipeRefreshLayout = (SwipeRefreshLayout)findViewById(R.id.swiperefreshlayout);
        swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                refresh();
            }
        });

        swipeList = (ListView)findViewById(R.id.swipelist);

        myList = new ArrayList<>();
        adapter = new ArrayAdapter<String>(
                this, android.R.layout.simple_list_item_1, myList);
        swipeList.setAdapter(adapter);
    }

    private void refresh(){
        //insert dummy string of current date/time
        String currentDateTime = DateFormat.getDateTimeInstance().format(new Date());
        myList.add(currentDateTime);
        swipeList.invalidateViews();
        swipeRefreshLayout.setRefreshing(false);
    }
}

In this example, the ListView items is updated in SwipeRefreshLayout.OnRefreshListener(). But normally refreshing involve longtime task, such as loading from Internet. The next example show how to refresh with longtime task run in background thread.

Implement ScaleGestureDetector on individual ImageView

Last example show Implementing ScaleGestureDetector on whole activity screen, to set scale of a ImageView. Now we modify to apply ScaleGestureDetector to individual ImageView, to scale the selected ImageView only.


Remark:
It can be noticed in the video, pinch-to-zoom cannot be detect after sometimes - I don't know why, but tap-and-slide still function as expected.

MainActivity.java

package com.blogspot.android_er.androidscalegesturedetector;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {

    ImageView myImage1, myImage2;

    private ScaleGestureDetector scaleGestureDetector1, scaleGestureDetector2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myImage1 = (ImageView)findViewById(R.id.myimage1);
        myImage2 = (ImageView)findViewById(R.id.myimage2);

        scaleGestureDetector1 = new ScaleGestureDetector(
                this, new MySimpleOnScaleGestureListener(myImage1));
        scaleGestureDetector2 = new ScaleGestureDetector(
                this, new MySimpleOnScaleGestureListener(myImage2));

        myImage1.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                scaleGestureDetector1.onTouchEvent(event);
                return true;
            }
        });

        myImage2.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                scaleGestureDetector2.onTouchEvent(event);
                return true;
            }
        });
    }


    private class MySimpleOnScaleGestureListener
            extends ScaleGestureDetector.SimpleOnScaleGestureListener{

        ImageView viewMyImage;

        float factor;

        public MySimpleOnScaleGestureListener(ImageView iv) {
            super();
            viewMyImage = iv;
            factor = 1.0f;
        }

        @Override
        public boolean onScale(ScaleGestureDetector detector) {

            float scaleFactor = detector.getScaleFactor() - 1;
            factor += scaleFactor;
            viewMyImage.setScaleX(factor);
            viewMyImage.setScaleY(factor);
            return true;
            //return super.onScale(detector);
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidscalegesturedetector.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:gravity="center"
        android:background="@android:color/black">
        <ImageView
            android:id="@+id/myimage1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/ic_launcher"
            android:background="#A00000"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:gravity="center"
        android:background="@android:color/darker_gray">
        <ImageView
            android:id="@+id/myimage2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/ic_launcher"
            android:background="#0000A0"/>
    </LinearLayout>

</LinearLayout>

Implement pinch-to-zoom with ScaleGestureDetector

Last post show how to implement ScaleGestureDetector, this post show how to implement pinch-to-zoom on ImageView with ScaleGestureDetector.


MainActivity.java

package com.blogspot.android_er.androidscalegesturedetector;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    TextView textMsg;
    ImageView myImage;

    private ScaleGestureDetector scaleGestureDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textMsg = (TextView)findViewById(R.id.msg);
        myImage = (ImageView)findViewById(R.id.myimage);

        scaleGestureDetector = new ScaleGestureDetector(
                this, new MySimpleOnScaleGestureListener(textMsg, myImage));
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        scaleGestureDetector.onTouchEvent(event);
        return true;
        //return super.onTouchEvent(event);
    }

    private class MySimpleOnScaleGestureListener
            extends ScaleGestureDetector.SimpleOnScaleGestureListener{

        TextView viewMessage;
        ImageView viewMyImage;

        float factor;

        public MySimpleOnScaleGestureListener(TextView v, ImageView iv) {
            super();
            viewMessage = v;
            viewMyImage = iv;
        }

        @Override
        public boolean onScaleBegin(ScaleGestureDetector detector) {
            factor = 1.0f;
            return true;
            //return super.onScaleBegin(detector);
        }

        @Override
        public boolean onScale(ScaleGestureDetector detector) {

            float scaleFactor = detector.getScaleFactor() - 1;
            factor += scaleFactor;
            viewMessage.setText(String.valueOf(scaleFactor)
                    + "\n" + String.valueOf(factor));
            viewMyImage.setScaleX(factor);
            viewMyImage.setScaleY(factor);
            return true;
            //return super.onScale(detector);
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidscalegesturedetector.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />
    <TextView
        android:id="@+id/msg"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textStyle="bold"
        android:textSize="24sp"/>
    <ImageView
        android:id="@+id/myimage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher"/>
</LinearLayout>

Next:
- Implement ScaleGestureDetector on individual ImageView

Android example: ScaleGestureDetector

android.view.ScaleGestureDetector detects scaling transformation gestures using the supplied MotionEvents. The ScaleGestureDetector.OnScaleGestureListener callback will notify users when a particular gesture event has occurred.


MainActivity.java

package com.blogspot.android_er.androidscalegesturedetector;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    TextView textMsg;

    private ScaleGestureDetector scaleGestureDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textMsg = (TextView)findViewById(R.id.msg);

        scaleGestureDetector = new ScaleGestureDetector(
                this, new MySimpleOnScaleGestureListener(textMsg));
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        scaleGestureDetector.onTouchEvent(event);
        return true;
        //return super.onTouchEvent(event);
    }

    private class MySimpleOnScaleGestureListener
            extends ScaleGestureDetector.SimpleOnScaleGestureListener{

        TextView viewMessage;

        public MySimpleOnScaleGestureListener(TextView v) {
            super();
            viewMessage = v;
        }

        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            float scaleFactor = detector.getScaleFactor();
            viewMessage.setText(String.valueOf(scaleFactor));
            return true;
            //return super.onScale(detector);
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidscalegesturedetector.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />
    <TextView
        android:id="@+id/msg"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textStyle="bold"
        android:textSize="24sp"/>
</LinearLayout>

Next:
- Implement pinch-to-zoom with ScaleGestureDetector

Detect user touch with GestureDetectorCompat

Android example to Detect user touch with GestureDetectorCompat:


MainActivity.java

package com.blogspot.android_er.androidgesturedetector;

import android.os.Bundle;
import android.support.v4.view.GestureDetectorCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private GestureDetectorCompat gestureDetectorCompat;
    TextView textInfo;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textInfo = (TextView)findViewById(R.id.info);

        gestureDetectorCompat = new GestureDetectorCompat(
                this, new MySimpleOnGestureListener(textInfo));
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        gestureDetectorCompat.onTouchEvent(event);
        return super.onTouchEvent(event);
    }

    private class MySimpleOnGestureListener
            extends GestureDetector.SimpleOnGestureListener{

        TextView textView;


        public MySimpleOnGestureListener(TextView v) {
            super();
            textView = v;
        }

        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            textView.append("\n- onSingleTapUp -");
            return super.onSingleTapUp(e);
        }

        @Override
        public void onLongPress(MotionEvent e) {
            textView.append("\n- onLongPress -");
            super.onLongPress(e);
        }

        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            textView.append("\n- onScroll -");
            return super.onScroll(e1, e2, distanceX, distanceY);
        }

        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            textView.append("\n- onFling -");
            return super.onFling(e1, e2, velocityX, velocityY);
        }

        @Override
        public void onShowPress(MotionEvent e) {
            textView.append("\n- onShowPress -");
            super.onShowPress(e);
        }

        @Override
        public boolean onDown(MotionEvent e) {
            textView.append("\n- onDown -");
            return super.onDown(e);
        }

        @Override
        public boolean onDoubleTap(MotionEvent e) {
            textView.append("\n- onDoubleTap -");
            return super.onDoubleTap(e);
        }

        @Override
        public boolean onDoubleTapEvent(MotionEvent e) {
            textView.append("\n- onDoubleTapEvent -");
            return super.onDoubleTapEvent(e);
        }

        @Override
        public boolean onSingleTapConfirmed(MotionEvent e) {
            textView.append("\n- onSingleTapConfirmed -");
            return super.onSingleTapConfirmed(e);
        }

        @Override
        public boolean onContextClick(MotionEvent e) {
            textView.append("\n- onContextClick -");
            return super.onContextClick(e);
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidgesturedetector.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/info"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="bottom"
        android:textStyle="italic" />
</LinearLayout>