[Android]实现带显示密码按钮的EditText(无内存泄露)

原理：

通过自定义View绘制显示密码按钮，当点击密码按钮的时候调用setInputType来更改属性。

解决方案：

就直接上代码了 

package com.finals.view;import com.example.test.R;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Paint.Style;import android.graphics.RectF;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.inputmethod.EditorInfo;import android.widget.EditText;public class PassEditText extends EditText {int mThumbWidth;int mThumbHeight;int offsetX;int offsetY;boolean isShowPass = false;Drawable mThumbDrawable;Bitmap mThumbDefault;public PassEditText(Context context, AttributeSet attrs) {super(context, attrs);InitDrawable(context, attrs);}public PassEditText(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);InitDrawable(context, attrs);}private void InitDrawable(Context context, AttributeSet attrs) {float density = context.getResources().getDisplayMetrics().density;TypedArray mTypedArray = context.obtainStyledAttributes(attrs, R.styleable.windows);mThumbDrawable = mTypedArray.getDrawable(R.styleable.windows_thumb);mThumbWidth = (int) mTypedArray.getDimension(R.styleable.windows_thumb_width, 20 * density);mThumbHeight = (int) mTypedArray.getDimension(R.styleable.windows_thumb_height, 20 * density);if (mThumbDrawable == null) {mThumbDefault = getThumbDefault();} else {mThumbDrawable.setBounds(0, 0, (int) mThumbWidth, (int) mThumbHeight);}mTypedArray.recycle();if (getInputType() != (EditorInfo.TYPE_TEXT_VARIATION_PASSWORD | EditorInfo.TYPE_CLASS_TEXT)) {isShowPass = true;}}@Overridepublic int getCompoundPaddingRight() {return super.getCompoundPaddingRight() + mThumbWidth;}@Overridepublic void draw(Canvas canvas) {super.draw(canvas);drawThumb(canvas);}void drawThumb(Canvas canvas) {offsetX = getWidth() - mThumbWidth - getPaddingRight();offsetY = (getHeight() - mThumbHeight) / 2;if (mThumbDrawable != null) {canvas.save();canvas.translate(getScrollX() + offsetX, getScrollY() + offsetY);mThumbDrawable.draw(canvas);canvas.restore();} else if (mThumbDefault != null) {canvas.drawBitmap(mThumbDefault, getScrollX() + offsetX, getScrollY() + offsetY, null);}}@Overridepublic boolean onTouchEvent(MotionEvent event) {int action = event.getAction();switch (action) {case MotionEvent.ACTION_DOWN:checkThumb(event);break;default:break;}return super.onTouchEvent(event);}void checkThumb(MotionEvent event) {float x = event.getX();float y = event.getY();if (x > offsetX && x < offsetX + mThumbWidth && y > offsetY && y < offsetY + mThumbHeight) {if (!isShowPass) {isShowPass = true;this.setInputType(EditorInfo.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD);} else {isShowPass = false;this.setInputType(EditorInfo.TYPE_TEXT_VARIATION_PASSWORD | EditorInfo.TYPE_CLASS_TEXT);}}}@Overrideprotected void onAttachedToWindow() {if (mThumbDrawable == null) {mThumbDefault = getThumbDefault();}super.onAttachedToWindow();}@Overrideprotected void onDetachedFromWindow() {if (mThumbDefault != null) {mThumbDefault.recycle();mThumbDefault = null;}super.onDetachedFromWindow();}/** * 创建默认图片 *  * @return */private Bitmap getThumbDefault() {float density = getContext().getResources().getDisplayMetrics().density;int stokenWidth = (int) (3 * density);Paint mPaint = new Paint();mPaint.setColor(Color.BLACK);mPaint.setStyle(Style.FILL);mPaint.setAntiAlias(true);Bitmap mBitmap = Bitmap.createBitmap(mThumbWidth, mThumbHeight, Config.ARGB_4444);Canvas mCanvas = new Canvas(mBitmap);mCanvas.drawCircle(mThumbWidth / 2, mThumbHeight / 2, mThumbWidth * 0.30F - stokenWidth, mPaint);mPaint.setStyle(Style.STROKE);mPaint.setStrokeWidth(stokenWidth);RectF oval = new RectF(stokenWidth, stokenWidth, mThumbWidth - stokenWidth, mThumbHeight - stokenWidth);mCanvas.drawArc(oval, -175, 170, false, mPaint);return mBitmap;}public boolean isShowPassword() {return isShowPass;}}