Android ActivityManager与WindowManager

    <uses-permission android:name="android.permission.GET_TASKS" />
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" /> <!-- 使用SYSTEM_ALERT_WINDOW时必须要加 -->
 

import android.app.Activity;
import android.app.ActivityManager;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.ViewGroup.LayoutParams;
import android.view.WindowManager;
import android.widget.TextView;

public class MainActivity extends Activity {
    private ActivityManager mActivityManager;

    private Handler popupHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
            case 0:
                String packageName = mActivityManager.getRunningTasks(1).get(0).topActivity.getPackageName();
                Log.e("log", packageName + System.currentTimeMillis());
                if (packageName.equals("com.some.app.name")) {
                    popupHandler.sendEmptyMessage(1);
                }
                if (isRunning) {
                    popupHandler.sendEmptyMessageDelayed(0, 3500);
                }
                break;
            case 1:
                Log.e("log", "mWindowManager");

                if (!isAdd) {
                    startActivity(new Intent(MainActivity.this, MainActivity.class));
                    mWindowManager.addView(mTrackingText, lp);
                    isAdd = true;
                }
                break;
            }
        }
    };
    WindowManager mWindowManager;
    private boolean isRunning = true;
    WindowManager.LayoutParams lp;
    TextView mTrackingText;
    boolean isAdd;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mActivityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
        mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
        mTrackingText = new TextView(MainActivity.this);
        mTrackingText.setTextColor(Color.BLUE);
        mTrackingText.setTextSize(55);
        mTrackingText.setText("00:00");
        lp = new WindowManager.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.TYPE_APPLICATION,
                WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
                PixelFormat.TRANSLUCENT);
        isRunning = true;
        popupHandler.sendEmptyMessageDelayed(0, 3500);
    }
}