Question

你知道http://code.google.com/p/mobile-anarchy-widgets/wiki/JoystickView的这个JoystickView吗？好吧，我试图实现它。没有问题。我无法改变它的大小，因为我以编程方式添加了它。我以某种方式找到了如何改变大小，但现在它被卡在左上角，我发现的三个小时的一切都让我在LayoutParams param上出现了NullPointerException我已经创建或被拒绝因为它不是＆＃cast; t castable或者开头的东西。

public class GameActivity extends Activity implements JoystickMovedListener{

private GraphicsHolder mGraphicsHolder;
private String TAG = "GameActivity";

/*
 * creates a new GraphicsHolder and sets it its ContentView
 * the GraphicsThread is being included in the GraphicsHolder
 */
@Override
protected void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    Log.d(TAG, "created");

    FrameLayout gameScreen = new FrameLayout(this);

    mGraphicsHolder = new GraphicsHolder(this);

    JoystickView Joystick = new JoystickView(this);


    // I need to set the Gravity HERE


    Joystick.setLayoutParams(new RelativeLayout.MarginLayoutParams(500,500));

    gameScreen.addView(mGraphicsHolder);
    gameScreen.addView(Joystick);

    setContentView(gameScreen);
}
}

现在问我的问题：你能以某种方式以编程方式设置此视图的重力吗？

Answer 1

你可以试试这个

RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(500,500);
params.addRule(RelativeLayout.CENTER_IN_PARENT, RelativeLayout.TRUE);

Joystick.setLayoutParams(params);

Answer 2

尝试将重心设置为FrameLayout并使用ViewGroup.LayoutParams设置操纵杆LayoutParams：

FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT,FrameLayout.LayoutParams.MATCH_PARENT);
params.gravity = Gravity.CENTER;
gameScreen.setLayoutParams(params);

Joystick.setLayoutParams(new ViewGroup.LayoutParams(500,500));

Answer 3

试试这个。

FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) Joystick.getLayoutParams();
params.gravity = Gravity.TOP;// desired gravity

Joystick.setLayoutParams(params);

不要更改你的代码，只需在setContentView(gameScreen);希望它有效之后添加它

Answer 4

嗯，我找到了答案，但这是一种完全不同的方法，因为上述内容或我在别处找到的都不适合我。

我在onCreate方法中做了以下更改：

    mGraphicsHolder = new GraphicsHolder(this);

    LayoutInflater inflate = (LayoutInflater)
            getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    setContentView(mGraphicsHolder);

    getWindow().addContentView(inflate.inflate(
        R.layout.controllayout, null), new ViewGroup.LayoutParams(
        ViewGroup.LayoutParams.FILL_PARENT, 
        ViewGroup.LayoutParams.FILL_PARENT));

    Joystick = (JoystickView) getWindow().findViewById(R.id.joystickView1);
    Joystick.setOnJostickMovedListener(this);

现在我在XML布局上获得了操纵杆，但它实际上是有效的（至少在我没有其他工作的情况下），并且在布局等方面进行更改非常容易。

如何以编程方式设置视图的LayoutParams？

4 个答案: