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【转】Android getWidth和getMeasuredWidth

程序员文章站 2022-07-14 17:40:27
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以前做项目的时候用到过,也不是很明白,现在看了别人的总结,转来。。。

 

代码一

public class MainActivity extends Activity {

	private LinearLayout mBackgroundLayout;
	private TextViewTest mTextViewTest;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		mBackgroundLayout = new MyLayout(this);
		mBackgroundLayout.setLayoutParams(new LinearLayout.LayoutParams(
				LinearLayout.LayoutParams.FILL_PARENT,
				LinearLayout.LayoutParams.FILL_PARENT));

		mTextViewTest = new TextViewTest(this);

		mBackgroundLayout.addView(mTextViewTest);
		setContentView(mBackgroundLayout);
	}

	public class MyLayout extends LinearLayout {

		public MyLayout(Context context) {
			super(context);
		}

		@Override
		protected void onLayout(boolean changed, int l, int t, int r, int b) {
			super.onLayout(changed, l, t, r, b);
			Log.i("Tag", "--------------");
			View mView = getChildAt(0);
			mView.measure(0, 0);
		}

	}

	public class TextViewTest extends TextView {
		public TextViewTest(Context context) {
			super(context);
			setText("test test ");
		}

		@Override
		protected void onDraw(Canvas canvas) {
			super.onDraw(canvas);
			 measure(0, 0);
			Log.i("Tag", "width: " + getWidth() + ",height: " + getHeight());
			Log.i("Tag", "MeasuredWidth: " + getMeasuredWidth()
					+ ",MeasuredHeight: " + getMeasuredHeight());
		}

	}

}

 

出来的LOG

width: 78,height: 29
MeasuredWidth: 78,MeasuredHeight: 29

 

代码2

public class MainActivity extends Activity {

    private TextViewTest mTextViewTest;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mTextViewTest = new TextViewTest(this);
        setContentView(mTextViewTest);
    }

    public class TextViewTest extends TextView {
        public TextViewTest(Context context) {
            super(context);
            setText("test test ");
        }

        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
             measure(0, 0);
            Log.i("Tag", "width: " + getWidth() + ",height: " + getHeight());
            Log.i("Tag", "MeasuredWidth: " + getMeasuredWidth()
                    + ",MeasuredHeight: " + getMeasuredHeight());
        }

    }

}

 出来的log

width: 480,height: 724
MeasuredWidth: 78,MeasuredHeight: 29

 

getMeasuredWidth():API里面
The width of this view as measured in the most recent call to measure(). This should be used during measurement and layout calculations only.
得到的是在最近一次调用measure()方法测量后得到的view的宽度,它仅仅用在测量和layout的计算中。
所以此方法得到的是view的内容占据的实际宽度

 

总结:

getwidth(): view在设定好布局后整个view的宽度。

getMeasuredWidth(): 对view上的内容进行测量后得到的view内容占据的宽度,前提是你必须在父布局的onLayout()方法或者此view的onDraw()方法里调用measure(0,0);(measure 参数的值你可以自己定义),否则你得到的结果和getWidth()一样。

 

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