26
2017
09

拿到view真实宽高的4种方式

实例代码

public class MainActivity extends Activity {

    private TextView tv;

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


    }

    @Override
    protected void onStart() {
        super.onStart();
        //方式1 post方法
        tv.post(new Runnable() {

            @Override
            public void run() {
                int width = tv.getMeasuredWidth();
                int height = tv.getMeasuredHeight();
            }
        });

        //方式2 视图树
        ViewTreeObserver observer = tv.getViewTreeObserver();
        observer.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

            @Override
            public void onGlobalLayout() {
                    tv.getViewTreeObserver().removeGlobalOnLayoutListener(this);
                    int width = tv.getMeasuredWidth();
                    int height = tv.getMeasuredHeight();
            }
        });
    }

    //方式3 回调方法
    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        if(hasFocus){
            int width = tv.getMeasuredWidth();
            int height = tv.getMeasuredHeight();
        }
    }

        //方式4 测量一遍该控件
        // 参数1 测量控件mode 参数2 大小 
        int widthMeasureSpec=MeasureSpec.makeMeasureSpec(MeasureSpec.EXACTLY, measuredWidth);  // mode+size
        int heightMeasureSpec=MeasureSpec.makeMeasureSpec(MeasureSpec.AT_MOST, 1000);// 我的高度 最大是1000
        // 测量规则 宽度是一个精确的值width, 高度最大是1000,以实际为准
        tv.measure(widthMeasureSpec, heightMeasureSpec); // 通过该方法重新测量控件 
        int measuredHeight2 = tv.getMeasuredHeight();
}
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