Android_Layout 用代码得到对象的高宽

Android_Layout 用代码得到对象的高宽

当设定 ViewGroup.LayoutParams 的设定优先。




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

        Button button = new Button(getApplicationContext());
        button.setText("Button");
//        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(500, 500);
        ViewGroup viewGroup = (ViewGroup) findViewById(R.id.activity_main);
        button.setHeight(400);
        button.setWidth(400);
//        viewGroup.addView(button);
        viewGroup.addView(button, layoutParams);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                RelativeLayout.LayoutParams rl = (RelativeLayout.LayoutParams) ((Button) v).getLayoutParams();
                System.out.println(rl.height);
                System.out.println(rl.width);
                System.out.println(((Button) v).getHeight());
                System.out.println(((Button) v).getWidth());
            }
        });
    }


当>>>>
        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(500, 500);
        ViewGroup viewGroup = (ViewGroup) findViewById(R.id.activity_main);
        button.setHeight(400);
        button.setWidth(400);
        viewGroup.addView(button, layoutParams);

结果
I/System.out: 500
I/System.out: 500
I/System.out: 500
I/System.out: 500


当>>>>
        button.setText("Button");
//        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(500, 500);
        ViewGroup viewGroup = (ViewGroup) findViewById(R.id.activity_main);
        button.setHeight(400);
        button.setWidth(400);
        viewGroup.addView(button);

结果
I/System.out: -2
I/System.out: -2
I/System.out: 400
I/System.out: 400