android动画如何实现一张图片从左到右的显示出来

Question

不是从左边平移到右边的效果 就是图片位置不动 慢慢显示出来
图片不动，但是从左往右渐渐显示
左边显示，右边透明，透明部分渐渐变少的效果 求大神指点啊 要怎么做？用什么方法？

Answer 1

代码:
package com.my.ui;

import android.animation.ObjectAnimator;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;

/**

• Created by my
  */
  public class RenderingView extends View implements View.OnClickListener{
  //是否layout完成
  private boolean mInit;

  private Paint mPaint;

  private RectF mRectF;

  // 0 - 1
  private float mProgress;

  private Bitmap mCurBitmap;
  private Rect mBitmapRect;
  private RectF mDrawableRectF;

  private Rect mSrc;
  private RectF mDst;

  private static final int DEFAULT_ANIMATION_DURATION = 1000;

  private OnClickListener mClickListener;

  private ObjectAnimator mAnimator;

  public RenderingView(Context context) {
  this(context, null);
  }

  public RenderingView(Context context, AttributeSet attrs) {
  this(context, attrs, 0);
  }

  public RenderingView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  init();
  }

  private void init(){
  mInit = false;
  mPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
  mRectF = new RectF();
  mBitmapRect = new Rect();
  mDrawableRectF = new RectF();
  mSrc = new Rect();
  mDst = new RectF();
  mProgress = 0;
  mAnimator = ObjectAnimator.ofFloat(this, "progress", 1);
  mAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
  super.setOnClickListener(this);
  }

  @Override
  protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
  super.onLayout(changed, left, top, right, bottom);
  if(changed){
  doInit(getViewRect(this));
  }
  }

  /**

  • 获取某个View的正确的位置
  • @param view
  • @return */ public static RectF getViewRect(View view){ int vLeft, vTop; int location[] = new int[2]; view.getLocationInWindow(location); vLeft = location[0]; vTop = location[1]; RectF mViewRect = new RectF(vLeft, vTop, vLeft + view.getWidth(), vTop + view.getHeight()); return mViewRect; }

  @Override
  protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  if(mInit && mCurBitmap != null){
  mSrc.set(mBitmapRect.left, mBitmapRect.top, (int)(mBitmapRect.right * mProgress + 0.5f), mBitmapRect.bottom);
  mDst.set(mDrawableRectF.left, mDrawableRectF.top, mDrawableRectF.right * mProgress, mDrawableRectF.bottom);
  canvas.drawBitmap(mCurBitmap, mSrc, mDst, mPaint);
  }
  }

  private void doInit(RectF rectF){
  if(!mInit || !mRectF.equals(rectF)){
  mRectF.set(rectF);
  if(mCurBitmap != null){
  setInformation();
  }
  mInit = true;
  }
  }

  public float getProgress() {
  return mProgress;
  }

  public void setProgress(float progress) {
  this.mProgress = progress;
  invalidate();
  }

  public void setImageBitmap(Bitmap bitmap){
  mCurBitmap = bitmap;
  if (mCurBitmap != null && mInit) {
  setInformation();
  }
  }

  /**

  • 设置一些信息
  • 图片显示默认是fitCenter样式的 */ public void setInformation(){ float w = mCurBitmap.getWidth(); float h = mCurBitmap.getHeight(); float viewW = mRectF.width(); float viewH = mRectF.height(); mBitmapRect.set(0, 0, (int)w, (int)h); if(w / h > viewW / viewH){//顶着宽 float curH = h * viewW / w; mDrawableRectF.set(0, (viewH - curH) / 2, viewW, (viewH - curH) / 2 + curH); } else{//顶高 float curW = w * viewH / h; mDrawableRectF.set((viewW - curW) / 2, 0, (viewW - curW) / 2 + curW, viewH); } beginAnimation(DEFAULT_ANIMATION_DURATION); }

  public void beginAnimation(int duration){
  setProgress(0);
  mAnimator.cancel();
  mAnimator.setDuration(duration).start();
  }

  @Override
  public void setOnClickListener(OnClickListener l) {
  mClickListener = l;
  }

  @Override
  public void onClick(View v) {
  beginAnimation(DEFAULT_ANIMATION_DURATION);
  if(mClickListener != null){
  mClickListener.onClick(v);
  }
  }
  }

用法:
写在XML中然后,
RenderingView renderingView = (RenderingView)findViewById(R.id.renderview);
renderingView.setImageBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.test));