[Android]給EditText添加圖文hint

[Android]給EditText添加圖文hint
原因：有時候我們需要當沒有文字的時候背景顯示一個圖文混合的背景提示，這時候如果採用控制項疊加的做法效率會很低，所以我們可以採用重載View的onDraw方法解決方案：
這個是效果，那個搜尋方塊。

package com.finals.teltem.view;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.Paint.FontMetrics;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.widget.EditText;import com.finals.teltem.R;public class SearchView extends EditText {float searchSize = 0;float textSize = 0;int textColor = 0xFF000000;Drawable mDrawable;Paint paint;public SearchView(Context context, AttributeSet attrs) {super(context, attrs);InitResource(context, attrs);InitPaint();}private void InitResource(Context context, AttributeSet attrs) {TypedArray mTypedArray = context.obtainStyledAttributes(attrs, R.styleable.searchedit);float density = context.getResources().getDisplayMetrics().density;searchSize = mTypedArray.getDimension(R.styleable.searchedit_imagewidth, 18 * density + 0.5F);textColor = mTypedArray.getColor(R.styleable.searchedit_textColor, 0xFF848484);textSize = mTypedArray.getDimension(R.styleable.searchedit_textSize, 14 * density + 0.5F);mTypedArray.recycle();}private void InitPaint() {paint = new Paint(Paint.ANTI_ALIAS_FLAG);paint.setColor(textColor);paint.setTextSize(textSize);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);DrawSearchIcon(canvas);}private void DrawSearchIcon(Canvas canvas) {if (this.getText().toString().length() == 0) {float textWidth = paint.measureText("搜尋");float textHeight = getFontLeading(paint);float dx = (getWidth() - searchSize - textWidth - 8) / 2;float dy = (getHeight() - searchSize) / 2;canvas.save();canvas.translate(getScrollX() + dx, getScrollY() + dy);if (mDrawable != null) {mDrawable.draw(canvas);}canvas.drawText("搜尋", getScrollX() + searchSize + 8, getScrollY() + (getHeight() - (getHeight() - textHeight) / 2) - paint.getFontMetrics().bottom - dy, paint);canvas.restore();}}@Overrideprotected void onAttachedToWindow() {super.onAttachedToWindow();if (mDrawable == null) {try {mDrawable = getContext().getResources().getDrawable(com.finals.teltem.R.drawable.serarch);mDrawable.setBounds(0, 0, (int) searchSize, (int) searchSize);} catch (Exception e) {}}}@Overrideprotected void onDetachedFromWindow() {if (mDrawable != null) {mDrawable.setCallback(null);mDrawable = null;}super.onDetachedFromWindow();}public float getFontLeading(Paint paint) {FontMetrics fm = paint.getFontMetrics();return fm.bottom - fm.top;}}