本文实例讲述了Android编程中TextView宽度过大导致Drawable无法居中问题解决方法。分享给大家供大家参考,具体如下:
在做项目的时候,很多时候我们都要用到文字和图片一起显示,一般设置TextView的DrawableLeft、DrawableRight、DrawableTop、DrawableBottom就行了。但是有一种情况是当TextView的熟悉是fill_parent或者使用权重的时候并且设置了起Gravity的ceter的时候,Drawable图片是无法一起居中的,为了解决其,我们一般再套一层布局,然后设置TextView的熟悉是wrap_content,但是有时候嵌套过多的布局的时候,有可能发生*,所以必须要优化,下面说一下其中的一个解决方案。先上图
这个解决方案很粗糙,局限性很大,文字不能换行,换行之后就不准了,下面是源码:
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package com.example.testandroid;
import java.lang.ref.WeakReference;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.TextView;
public class DrawableTextView extends TextView {
private WeakReference<Bitmap> normalReference;
private WeakReference<Bitmap> pressReference;
private WeakReference<Bitmap> showReference;
private int normalColor = Color.WHITE, pressColor = Color.WHITE;
private String text;
private int textWidth = 0 ;
private int textHeight = 0 ;
public DrawableTextView(Context context) {
super (context);
}
public DrawableTextView(Context context, AttributeSet attrs) {
super (context, attrs);
}
public DrawableTextView(Context context, AttributeSet attrs, int defStyle) {
super (context, attrs, defStyle);
}
@Override
protected void onFinishInflate() {
super .onFinishInflate();
initText();
}
private void initText() {
text = super .getText().toString();
initVariable();
}
/**
* 初始化,测量Textview内容的长度,高度
*/
private void initVariable() {
textWidth = ( int ) (getPaint().measureText(text));
final Rect rect = new Rect();
getPaint().getTextBounds(text, 0 , 1 , rect);
textHeight = rect.height();
}
/**
* 设置TextView的内容
* @param text
*/
public void setText(String text) {
this .text = text;
initVariable();
invalidate();
}
/**
* 获取TextView内容
*/
public String getText() {
return text;
}
/**
* 设置TextView的Drawable内容,目前仅支持DrawableLeft
* @param normalDrawableId
* DrawableLeft的normal状态Id
* @param pressDrawableId
* DrawableLeft的press状态的Id(没有press状态,请传-1)
*/
public void setDrawableLeftId( final int normalDrawableId, final int pressDrawableId) {
normalReference = new WeakReference<Bitmap>(BitmapFactory.decodeResource(getResources(), normalDrawableId));
if (pressDrawableId != - 1 ) {
pressReference = new WeakReference<Bitmap>(BitmapFactory.decodeResource(getResources(), pressDrawableId));
}
showReference = normalReference;
invalidate();
}
/**
* 设置TextView的Color
* @param normalColor
* TextView normal状态的Color值
* @param pressDrawableId
* TextView press状态的Color值(如果没有press状态,请传与normal状态的值)
*/
public void setTextColor( final int normalColor, final int pressColor) {
this .normalColor = normalColor;
this .pressColor = pressColor;
getPaint().setColor(normalColor);
initVariable();
}
@Override
protected void onDraw(Canvas canvas) {
if (showReference != null && showReference.get() != null ) {
final int bitmapWidth = showReference.get().getWidth();
final int bitmapHeight = showReference.get().getHeight();
final int viewHeight = getHeight();
final int drawablePadding = getCompoundDrawablePadding();
final int start = (getWidth() - (bitmapWidth + drawablePadding + textWidth)) >> 1 ;
canvas.drawBitmap(showReference.get(), start, (viewHeight >> 1 ) - (bitmapHeight >> 1 ), getPaint());
/**
* 注意改方法,第三个参数y,本人也被误导了好久,原来在画文字的时候,y表示文字最后的位置(不是下笔点的起始位置)
* 所以为什么 是TextView高度的一半(中间位置) + 文字高度的一半 = 文字居中
*/
canvas.drawText(text, start + drawablePadding + bitmapWidth, (viewHeight >> 1 ) + (textHeight >> 1 ), getPaint());
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
if (pressReference != null && pressReference.get() != null ) {
showReference = pressReference;
}
getPaint().setColor(pressColor);
} else if (event.getAction() == MotionEvent.ACTION_UP) {
if (normalReference != null && normalReference.get() != null ) {
showReference = normalReference;
}
getPaint().setColor(normalColor);
}
invalidate();
return super .onTouchEvent(event);
}
}
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xml布局:
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< com.example.testandroid.DrawableTextView
android:id = "@+id/my_textview"
android:layout_width = "fill_parent"
android:layout_marginTop = "20dp"
android:background = "@drawable/text_selector"
android:drawablePadding = "8dp"
android:textColor = "@color/standard_orange"
android:layout_height = "wrap_content"
android:padding = "15dp"
android:textSize = "16sp"
android:text = "有Drawable的TextView" />
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调用代码:
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DrawableTextView drawableTextView = (DrawableTextView) getView().findViewById(R.id.my_textview);
drawableTextView.setDrawableLeftId(R.drawable.bg_btn_delete_normal, R.drawable.bg_btn_delete_pressed);
drawableTextView.setTextColor(getResources().getColor(R.color.standard_orange), getResources().getColor(R.color.standard_white));
drawableTextView.setText( "我在动态修改Text啦" );
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其实还有更加方便的方法,下面朋友借鉴某个网友的代码(地址我就不知道了):
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@Override
protected void onDraw(Canvas canvas) {
Drawable[] drawables = getCompoundDrawables();
if (drawables != null ) {
Drawable drawableLeft = drawables[ 0 ];
if (drawableLeft != null ) {
final float textWidth = getPaint().measureText(getText().toString());
final int drawablePadding = getCompoundDrawablePadding();
final int drawableWidth = drawableLeft.getIntrinsicWidth();
final float bodyWidth = textWidth + drawableWidth + drawablePadding;
canvas.translate((getWidth() - bodyWidth) / 2 , 0 );
}
}
super .onDraw(canvas);
}
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xml布局:
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<com.example.testandroid.DrawableTextView
android:id= "@+id/my_textview"
android:layout_width= "fill_parent"
android:layout_marginTop= "20dp"
android:background= "@drawable/text_selector"
android:drawablePadding= "8dp"
android:drawableLeft= "@drawable/clear_edittext_selector"
android:textColor= "@color/text_color_selector"
android:layout_height= "wrap_content"
android:padding= "15dp"
android:textSize= "16sp"
android:text= "有Drawable的TextView" />
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嗯,自己写这个东西,也学到了一些东西,大家有什么更好的方法,大家可以讨论一下。
希望本文所述对大家Android程序设计有所帮助。