Floating view on Android screen

问题:

I was trying to make a floating view which user can drag around on the screen.

The idea is to launch a service and then inflate a view on the screen.

But there's a problem, instead of taking the event belongs to itself, it takes all the user input event.

here's my code: the manifest.xml:

    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.floatandroidpractice"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.floatandroidpractice.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service android:name="com.example.floatandroidpractice.WalkingIconService" />
    </application>

</manifest>

the floating view which can be drag around:

package com.example.floatandroidpractice;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.MotionEvent;
import android.view.View;

public class littleIconView extends View {
    private float viewX;
    private float viewY;
    private Paint mPaint;
    private Bitmap androidIcon;

    public littleIconView(Context context) {
        super(context);
        mPaint = new Paint();
        mPaint.setColor(Color.BLACK);
        androidIcon = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);

    }

    @Override
    public void onDraw(Canvas cvs) {
        cvs.drawBitmap(androidIcon, viewX - androidIcon.getWidth() / 2, viewY - androidIcon.getHeight()
                / 2, mPaint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        boolean touchedX = Math.abs(viewX - event.getX()) > androidIcon.getWidth();
        boolean touchedY = Math.abs(viewY - event.getY()) > androidIcon.getHeight();
        boolean isValidTouch = !touchedX && !touchedY;
        if (isValidTouch) {
            if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() == MotionEvent.ACTION_MOVE
                    || event.getAction() == MotionEvent.ACTION_UP) {
                viewX = event.getX();
                viewY = event.getY();
            }
            invalidate();
            return true;

        }
        else
            return false;
    }
}

and the service:

package com.example.floatandroidpractice;
import android.app.Service;
import android.content.Intent;
import android.graphics.PixelFormat;
import android.os.IBinder;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;

public class WalkingIconService extends Service {

    @Override
    public void onCreate() {
        super.onCreate();

    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        littleIconView a = new littleIconView(getApplicationContext());
        LayoutParams mLayoutParams = new WindowManager.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 0, 0, PixelFormat.TRANSPARENT);
        WindowManager mWindowManager = (WindowManager) this.getSystemService(WINDOW_SERVICE);
        mLayoutParams.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL | LayoutParams.FLAG_NOT_FOCUSABLE
                | LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH |
                LayoutParams.FLAG_LAYOUT_INSET_DECOR | LayoutParams.FLAG_LAYOUT_IN_SCREEN;
        mWindowManager.addView(a, mLayoutParams);
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

}

full project: https://github.com/shanwu/shanwu_coding_base/tree/xxx/floatAndroidPractice

回答1:

I tried your way of drawing the image on a canvas, but that didn't go anywhere. An example, EatHeat's github, where I learned from. Maybe this can get you rolling in the right direction, maybe not, but it worked for me.

WalkingIconService.java

package ...
//imports

public class WalkingIconService extends Service {
    private WindowManager mWindowManager;
    private ImageView image;

    public void onCreate() {
        super.onCreate();
        image = new ImageView(this);

        image.setImageResource(R.drawable.ic_launcher);

        mWindowManager = (WindowManager)getSystemService(WINDOW_SERVICE);

        final LayoutParams paramsF = new WindowManager.LayoutParams(
            LayoutParams.WRAP_CONTENT,
            LayoutParams.WRAP_CONTENT,
            LayoutParams.TYPE_PHONE,
            LayoutParams.FLAG_NOT_FOCUSABLE,
            PixelFormat.TRANSLUCENT);

        paramsF.gravity = Gravity.TOP | Gravity.LEFT;
        paramsF.x=0;
        paramsF.y=100;
        mWindowManager.addView(image, paramsF);

        try{

            image.setOnTouchListener(new View.OnTouchListener() {
                WindowManager.LayoutParams paramsT = paramsF;
                private int initialX;
                private int initialY;
                private float initialTouchX;
                private float initialTouchY;
                @Override
                public boolean onTouch(View v, MotionEvent event) {
                    switch(event.getAction()){
                    case MotionEvent.ACTION_DOWN:
                        initialX = paramsF.x;
                        initialY = paramsF.y;
                        initialTouchX = event.getRawX();
                        initialTouchY = event.getRawY();
                        break;
                    case MotionEvent.ACTION_UP:
                        break;
                    case MotionEvent.ACTION_MOVE:
                        paramsF.x = initialX + (int) (event.getRawX() - initialTouchX);
                        paramsF.y = initialY + (int) (event.getRawY() - initialTouchY);
                        mWindowManager.updateViewLayout(v, paramsF);
                        break;
                    }
                    return false;
                }
            });
        } catch (Exception e){
            e.printStackTrace();
        }
    }

    @Overrride
    public void onDestroy(){
        super.onDestory();
    }

}

MainActivity.java

package ...
//imports

public class MainActivity extends Activity {

    @Override
    public void onCreate(icicle) {
        super.onCreate(icicle);
        setcontentView(R.layout.activity_main);
        Button b = (Button)findViewById(R.id.tv);
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //toast
                startService(new Intent(MainActivity.this, WalkingIconService.class));
            }
        });
        //stopService (from my original code)
        Button stop = (Button)findViewById.(R.id.btnStop);
        stop.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService(new Intent(MainActivity.this, WalkingIconService.class));
            }
        });
    }
}

回答2:

By default, View will take up the entire available space when laid out with WRAP_CONTENT. You need to either explicitly specify the view size in your WindowManager.LayoutParams, override View.onMeasure, or (ideally) extend ImageView rather than View.

回答3:

from api 23+,before start service check Settings.ACTION_MANAGE_OVERLAY_PERMISSION permission:

 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if (!Settings.canDrawOverlays(ConversationsActivityWithSpam.this)) {
                    Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
                            Uri.parse("package:" + getPackageName()));
                    startActivityForResult(intent, 16);
                    return false;
                }
            }