Android P FreeForm自由窗口模式简单实现

开启系统FreeForm模式。
adb shell settings put global enable_freeform_support 1
adb shell settings put global force_resizable_activities 1

/frameworks/native/data/etc/android.software.freeform_window_management.xml
push到目录system/etc/permissions/

代码如下：

public class MainActivity extends AppCompatActivity {

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

        Intent intent = new Intent(this, FreeFormActivity.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_LAUNCH_ADJACENT | Intent.FLAG_ACTIVITY_NEW_TASK);

        //ActivityOptions activityOptions = ActivityOptions.makeBasic();
        //activityOptions.setLaunchWindowingMode(5);
        ActivityOptions activityOptions = getActivityOptions(this);
        int left = 200;
        int top = 100;
        int right = 600;
        int bottom = 200;
        activityOptions.setLaunchBounds(new Rect(left,top,right,bottom));
        Bundle bundle = activityOptions.toBundle();
        startActivity(intent,bundle);
    }

    public static ActivityOptions getActivityOptions(Context context) {
        ActivityOptions options = ActivityOptions.makeBasic();
        int freeform_stackId = 5;
        try {
            Method method = ActivityOptions.class.getMethod("setLaunchWindowingMode", int.class);
            method.invoke(options, freeform_stackId);
            Log.i("FreeForm","sunxiaolin,getActivityOptions freeform_stackId = " + freeform_stackId);
        } catch (Exception e) {
            /* Gracefully fail */
            Log.i("FreeForm","sunxiaolin,getActivityOptions e = " + e);
        }

        return options;
    }
}

FreeFormActivity是一个只显示文本“Hello FreeForm!”的Activity.

效果图：