當需要擴展android原生TextView的時候,比如需要給TextView默認加上10像素的顏色邊框時,當設置寬高為wrap_content時,高度並不好處理。網上大部分人雲亦雲的說設置一個默認值,然后根據測量模式,取 MeasureSpec.getSize(widthMeasureSpec)和默認值中的較小值,我想說就是扯淡。比如說我需要的寬度是200px,默認值是50px,此時寬度肯定不夠。先看如下代碼

package com.example.customview.view; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.util.AttributeSet; import android.util.Log; import android.view.View.MeasureSpec; import android.view.WindowManager; import android.widget.TextView; public class CustomTextView extends TextView { private Paint paint1; private Paint paint2; public CustomTextView(Context context) { super(context, null); } public CustomTextView(Context context, AttributeSet attrs) { super(context, attrs); initView(context, attrs); // TODO Auto-generated constructor stub } private void initView(Context context, AttributeSet attrs) { paint1 = new Paint(); paint1.setColor(getResources().getColor(android.R.color.holo_blue_dark)); paint1.setStyle(Paint.Style.FILL); paint2 = new Paint(); paint2.setStyle(Paint.Style.FILL); paint2.setColor(Color.GREEN); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // // TODO Auto-generated method stub super.onMeasure(widthMeasureSpec, heightMeasureSpec); int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); if(heightMode == MeasureSpec.AT_MOST&&widthMode == MeasureSpec.AT_MOST){ //高度寬度為wrap_content時 setMeasuredDimension(getMeasuredWidth()+20, getMeasuredHeight()+20); } } @Override protected void onDraw(Canvas canvas) { Log.e("CustomTextView", "widthSize" + getMeasuredWidth() + "heightSize" + getMeasuredHeight()); canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredWidth(), paint1); canvas.drawRect(10, 10, getMeasuredWidth() - 10, getMeasuredHeight() - 10, paint2); canvas.translate(10, 10); super.onDraw(canvas); } }
注意:
if(heightMode == MeasureSpec.AT_MOST&&widthMode == MeasureSpec.AT_MOST){ //高度寬度為wrap_content時 setMeasuredDimension(getMeasuredWidth()+20, getMeasuredHeight()+20); }
通過調用TextView的getMeasuredWidth(),getMeasuredHeight()的方法獲取獲取不加邊框時的寬高,在加上適當的偏移量,就能實現了。
用法如下:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:orientation="vertical" > <com.example.customview.view.CustomTextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="參與人數"/> </LinearLayout>
運行結果如下: