搜索网站 模板,可以用手机制作app的软件,seo入门教程视频,推销网站的方法在系统的相册中,观看相片就可以用多个手指进行缩放.要实现这个功能,只需要这几步:1.新建项目,在项目中新建一个ZoomImage.javapublic class ZoomImageView extends View {//初始化状态常量public static final int STATUS_INIT1;//图片放大状态常量public static final int STA…在系统的相册中,观看相片就可以用多个手指进行缩放.要实现这个功能,只需要这几步:1.新建项目,在项目中新建一个ZoomImage.java public class ZoomImageView extends View {     //初始化状态常量     public static final int STATUS_INIT1;     //图片放大状态常量     public static final int STATUS_ZOOM_OUT2;     //图片缩小状态常量     public static final int STATUS_ZOOM_IN3;     //图片拖动状态的常量     public static final int STATUS_MOVE4;     //对图片进行移动和缩放的矩阵     private Matrix matrixnew Matrix();     //需要处理的Bitmap对象     private Bitmap sourceBitmap;     //记录当前的操作状态     private int currentStatus;          //ZoomImageView的宽度     private int width;     //ZoomImageView的高度     private int height;               //记录两指同时放在屏幕上时,中心点的横坐标     private float centerPointX;     //记录两指同时放在屏幕上时,中心点的纵坐标     private float centerPointY;          //记录当前图片的宽度     private float currentBitmapWidth;     //记录当前图片的高度     private float currentBitmapHeight;          //记录上次手指移动时的横坐标     private float lastXMove-1;     //记录上次手指移动时的纵坐标     private float lastYMove-1;          //记录手指在横坐标上的距离     private float moveDistanceX;     //记录手指在纵坐标上的距离     private float moveDistanceY;          //记录图片在矩阵上横向偏移值     private float totalTranslateX;     //记录图片在矩阵上纵向偏移值     private float totalTranslateY;          //记录图片在矩阵上总缩放比例     private float totalRatio;          //记录手指移动的距离造成的缩放比例     private float scaledRatio;          //记录图片初始化时的缩放比例     private float initRatio;          //记录上次手指之间的距离     private double lastFingerDis;          //初始状态  设置当前操作状态为STATUS_INIT     public ZoomImageView(Context context, AttributeSet attrs) {         super(context, attrs);         currentStatusSTATUS_INIT;     }     //将待展示的图片设置进来     public void setImageBitmap(Bitmap bitmap){         sourceBitmapbitmap;         invalidate();     }     Override     protected void onLayout(boolean changed, int left, int top, int right,             int bottom) {         super.onLayout(changed, left, top, right, bottom);         if(changed){             widthgetWidth();             heightgetHeight();         }     }          Override     public boolean onTouchEvent(MotionEvent event) {         switch (event.getActionMasked()) {         case MotionEvent.ACTION_POINTER_DOWN:             if(event.getPointerCount()2){                 lastFingerDisdistanceBetweenFingers(event);  //两指间按下的距离             }             break;         case MotionEvent.ACTION_MOVE:             if(event.getPointerCount()1){  //如果只有一个手指在屏幕上 则为拖动模式                 float xMoveevent.getX();                 float yMoveevent.getY();                 if(lastXMove-1lastYMove-1){                     lastXMovexMove;                     lastYMoveyMove;                 }                 currentStatusSTATUS_MOVE;                 moveDistanceXxMove-lastXMove;                 moveDistanceYyMove-lastYMove;                 //进行边界检查 不允许拖出边界                 if(totalTranslateXmoveDistanceX0){                     moveDistanceX0;                 }                 else if(width-(totalTranslateXmoveDistanceX)currentBitmapWidth){                     moveDistanceX0;                 }                 if(totalTranslateYmoveDistanceY0){                     moveDistanceY0;                 }                 else if(height-(totalTranslateYmoveDistanceY)currentBitmapHeight){                     moveDistanceY0;                 }                                  //调用onDraw()方法绘制图片                 invalidate();                 lastXMovexMove;                 lastYMoveyMove;             }             else if(event.getPointerCount()2){                 //有两个手指在屏幕上移动  为缩放状态                 centerPointBetweenFingers(event);                 double fingerDisdistanceBetweenFingers(event);                 if(fingerDislastFingerDis){                     currentStatusSTATUS_ZOOM_OUT;                 }                 else{                     currentStatusSTATUS_ZOOM_IN;                 }                 //进行缩放倍数检查                 if((currentStatusSTATUS_ZOOM_OUTtotalRatio4*initRatio)||(currentStatusSTATUS_ZOOM_INtotalRatioinitRatio)){                     scaledRatio(float) (fingerDis/lastFingerDis);  //需要缩放的比例                     totalRatiototalRatio*scaledRatio;                     if(totalRatio4*initRatio){                         totalRatio4*initRatio;                     }                     else if(totalRatioinitRatio){                         totalRatioinitRatio;                     }                     //调用onDraw                     invalidate();                     lastFingerDisfingerDis;                 }             }             break;         case MotionEvent.ACTION_POINTER_UP:             if(event.getPointerCount()2){                 lastXMove-1;                 lastYMove-1;             }             break;         case MotionEvent.ACTION_UP:             lastXMove-1;             lastYMove-1;             break;         default:             break;         }         return true;     }          Override     protected void onDraw(Canvas canvas) {         super.onDraw(canvas);         switch (currentStatus) {         case STATUS_ZOOM_OUT:         case STATUS_ZOOM_IN:             zoom(canvas);             break;         case STATUS_MOVE:             move(canvas);             break;         case STATUS_INIT:             initBitmap(canvas);             break;         default:             canvas.drawBitmap(sourceBitmap, matrix, null);             break;         }     }          //初始化显示图片     private void initBitmap(Canvas canvas){         if(sourceBitmap!null){             matrix.reset();             int bitmapWidthsourceBitmap.getWidth();             int bitmapHeightsourceBitmap.getHeight();             if(bitmapWidthwidth||bitmapHeightheight){//如果图片的宽度或高度有大于屏幕宽高                 if(bitmapWidth-widthbitmapHeight-height){    //判断这张图片 是宽度长  还是高度长  如果是宽度长,则按宽度的那边进行压缩  高度也等比例压缩                     float radiowidth/(bitmapWidth*1.0f);     //需要压缩的比例                       matrix.postScale(radio,radio);             //缩放矩阵比例                     float translateY(height-(bitmapHeight*radio))/2f;   //因为是按宽度进行压缩  所以宽度应该是占满全屏  这时候还应该将图片Y轴向下移动                     //在纵坐标上进行偏移 以保证图片居中显示                     matrix.postTranslate(0, translateY);                     totalTranslateYtranslateY;                     totalRatioinitRatioradio;                 }                 else{                     //当图片高度大于屏幕高度时                     float radioheight/(bitmapHeight*1.0f);                     matrix.postScale(radio, radio);                     float translateX(width-(bitmapWidth*radio))/2f;                     //在横坐标上进行偏移                      matrix.postTranslate(translateX, 0);//平移                     totalTranslateXtranslateX;                     totalRatioinitRatioradio;                 }             }             else{                 //当图片的宽度与高度都小于屏幕宽高时,让图片居中显示                 float translateX(width-sourceBitmap.getWidth())/2f;                 float translateY(height-sourceBitmap.getHeight())/2f;                 matrix.postTranslate(translateX, translateY);                 totalTranslateXtranslateX;                 totalTranslateYtranslateY;                 totalRatioinitRatio1f;                 currentBitmapHeightbitmapHeight;                 currentBitmapWidthbitmapWidth;             }             canvas.drawBitmap(sourceBitmap, matrix, null);         }     }          //对图片进行缩放处理     private void zoom(Canvas canvas){         matrix.reset();         //将图片按照比例缩放         matrix.postScale(totalRatio, totalRatio);         float scaledWidthsourceBitmap.getWidth()*totalRatio;         float scaledHeightsourceBitmap.getHeight()*totalRatio;                  float translateX0f;         float translateY0f;                  //如果当前图片宽度小于屏幕宽度  则按屏幕中心点 进行水平缩放,否则按两指中线点的横坐标进行缩放         if(currentBitmapWidthwidth){             translateX(width-scaledWidth)/2f;         }         else{             translateXtotalTranslateX*scaledRatiocenterPointX*(1-scaledRatio);                          //进入边界检查 ,保证图片缩放后水平方向不会偏移屏幕             if(translateX0){                 translateX0;             }             else if(width-translateXscaledWidth){                 translateXwidth-scaledWidth;             }         }         if(currentBitmapHeightheight){             translateY(height-scaledHeight)/2f;         }         else{             translateYtotalTranslateY*scaledRatiocenterPointY*(1-scaledRatio);             //进行边界检查             if(translateY0){                 translateY0;             }             else if(height-translateYscaledHeight){                 translateYheight-scaledHeight;             }         }         //缩放后对图片进行偏移 保证缩放后中心点位置不变         matrix.postTranslate(translateX, translateY);         totalTranslateXtranslateX;         totalTranslateYtranslateY;         currentBitmapWidthscaledWidth;         currentBitmapHeightscaledHeight;         canvas.drawBitmap(sourceBitmap, matrix, null);     }          //对图片进行平移处理     private void move(Canvas canvas){         matrix.reset();         //根据手指移动的距离计算总偏移量         float translateXtotalTranslateXmoveDistanceX;         float translateYtotalTranslateYmoveDistanceY;         //按照已有的缩放比例对图片缩放         matrix.postScale(totalRatio, totalRatio);         //根据移动距离进行偏移         matrix.postTranslate(translateX, translateY);         totalTranslateXtranslateX;         totalTranslateYtranslateY;         canvas.drawBitmap(sourceBitmap, matrix, null);     }          //计算两个手指的距离     private double distanceBetweenFingers(MotionEvent event){         float disXMath.abs(event.getX(0)-event.getX(1));         float disYMath.abs(event.getY(0)-event.getY(1));         return Math.sqrt(disX*disXdisY*disY);        }     //计算两个手指之间中心点的坐标     private void centerPointBetweenFingers(MotionEvent event){         float xPoint0event.getX(0);         float yPoint0event.getY(0);         float xPoint1event.getX(1);         float yPoint1event.getY(1);         centerPointX(xPoint0xPoint1)/2;         centerPointY(yPoint0yPoint1)/2;     } }2.打开activity_main.xml com.example.bitmaptest.ZoomImageView xmlns:androidhttp://schemas.android.com/apk/res/android     xmlns:toolshttp://schemas.android.com/tools     android:layout_widthmatch_parent     android:layout_heightmatch_parent     android:idid/zoom_image     tools:contextcom.example.bitmaptest.MainActivity       /com.example.bitmaptest.ZoomImageView  3.打开MainActivity.java public class MainActivity extends ActionBarActivity {     private Bitmap bitmap;     Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         ZoomImageView zoomImage(ZoomImageView) findViewById(R.id.zoom_image);         bitmapBitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);         if(bitmap!null){             zoomImage.setImageBitmap(bitmap);         }     } }  来自为知笔记(Wiz)转载于:https://www.cnblogs.com/aibuli/p/76d1cd14cb1dcf018198fba314bb3509.html