详解android6.0版本下悬浮窗实现

悬浮窗在安卓中实现起来还是比较容易的，这几天在网上温习了相关资料，运行在我安卓6.0手机上才发现，原来在6.0手机上不是行的。

第一反应肯定是权限相关问题，做了相关处理后，果然让悬浮窗原形毕露了。直接贴代码。

public class MainActivity extends AppCompatActivity {
 private static final int ALERT_WINDOW_PERMISSION_CODE = 100;
 private Button start_float;

@Override
 protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);
   start_float = (Button) findViewById(R.id.start_float);
   this.start_float.setOnClickListener(new View.OnClickListener() {
     @Override
     public void onClick(View view) {
       if (Build.VERSION.SDK_INT > 22) {
         sdk23Permission();
       } else {
         startService(new Intent(MainActivity.this, FloatService.class));
         finish();
       }
     }
   });
 }

/**
  * @description 安卓6.0下权限处理
  * @author ldm
  * @time 2017/3/20 15:00
  */
 public void sdk23Permission() {
   if (!Settings.canDrawOverlays(this)) {
     Toast.makeText(MainActivity.this, "当前无权限使用悬浮窗，请授权！", Toast.LENGTH_SHORT).show();
     Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
         Uri.parse("package:" + getPackageName()));
     startActivityForResult(intent, ALERT_WINDOW_PERMISSION_CODE);
   } else {
     startService(new Intent(MainActivity.this, FloatService.class));
     finish();
   }
 }

/**
  * 用户返回
  */
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
   if (requestCode == ALERT_WINDOW_PERMISSION_CODE) {
     if (!Settings.canDrawOverlays(this)) {
       Toast.makeText(MainActivity.this, "权限授予失败，无法开启悬浮窗", Toast.LENGTH_SHORT).show();
     } else {
       startService(new Intent(MainActivity.this, FloatService.class));
       finish();
     }

}
 }
}

对应Service:

public class FloatService extends Service {
 @Nullable
 @Override
 public IBinder onBind(Intent intent) {
   return null;
 }

@Override
 public void onCreate() {
   FloatViewUtils.getInstance(this).addFloatView();
   super.onCreate();
 }
}

简单地FloatView:

public class FloatView extends View {
 public static final int WIDTH = 150;
 public static final int HEIGHT = 150;
 private Paint circlePaint;
 private Paint textPaint;
 private static final String text = "50％";

public FloatView(Context context) {
   this(context, null, 0);
 }

public FloatView(Context context, @Nullable AttributeSet attrs) {
   this(context, attrs, 0);
 }

public FloatView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
   super(context, attrs, defStyleAttr);
   initPaints();
 }

/**
  * @description 初始化相关画笔Paint
  * @author ldm
  * @time 2017/3/20
  */
 private void initPaints() {
   circlePaint = new Paint();
   circlePaint.setAntiAlias(true);
   circlePaint.setColor(Color.GRAY);
   textPaint = new Paint();
   //设置抗锯齿
   textPaint.setAntiAlias(true);
   //设置字体大小
   textPaint.setTextSize(30);
   //设置颜色
   textPaint.setColor(Color.WHITE);
   //设置（仿）粗体
   textPaint.setFakeBoldText(true);
 }

@Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
   setMeasuredDimension(WIDTH, HEIGHT);
 }

@Override
 protected void onDraw(Canvas canvas) {
   super.onDraw(canvas);
   canvas.drawCircle(WIDTH / 2, HEIGHT / 2, WIDTH / 2, circlePaint);
   float textWidth = textPaint.measureText(text);
   float x = WIDTH / 2 - textWidth / 2;
   Paint.FontMetrics fms = textPaint.getFontMetrics();
   float dy = -(fms.descent + fms.ascent) / 2;
   float y = HEIGHT / 2 + dy;
   canvas.drawText(text, x, y, textPaint);
 }
}

以及FloatView管理工具类：

public class FloatViewUtils {
 private static FloatViewUtils instance;
 private Context mContext;
 private WindowManager manager;
 private FloatView floatView;

private FloatViewUtils(Context mContext) {
   this.mContext = mContext;
   manager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
   floatView = new FloatView(mContext);
 }

public static FloatViewUtils getInstance(Context mContext) {
   if (null == instance) {
     synchronized (FloatViewUtils.class) {
       if (null == instance) {
         instance = new FloatViewUtils(mContext);
       }
     }
   }
   return instance;
 }

public void addFloatView() {
   WindowManager.LayoutParams lp = new WindowManager.LayoutParams();
   //悬浮窗口大小
   lp.width = floatView.WIDTH;
   lp.height = floatView.HEIGHT;
   // 调整悬浮窗口位置
   lp.gravity = Gravity.LEFT | Gravity.CENTER;
   // 以屏幕左上角为原点，设置x、y初始值
//    lp.x = 0;
//    lp.y = 0;
   //设置悬浮窗口类型
   lp.type = WindowManager.LayoutParams.TYPE_PHONE;
   //设置悬浮窗口不接受焦点及触摸事件
   lp.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;
   //设置图片格式，效果为背景透明
   lp.format = PixelFormat.RGBA_8888;
   manager.addView(floatView, lp);
 }
}

最后不要忘记在AndroidManifest.xml中添加权限（当然还有注册Service）：

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

来源：http://blog.csdn.net/true100/article/details/64126121