圖片隨手勢放大縮小功能
阿新 • • 發佈：2018-12-17
主介面：
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".MainActivity"> <ImageView android:layout_width="200dp" android:layout_height="200dp" android:padding="20dp" android:id="@+id/img_init" android:src="@drawable/girl"/> </LinearLayout>
圖片放大介面：
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#000000" > <com.example.test15.picturemanage.ZoomImageView android:layout_width="fill_parent" android:layout_height="fill_parent" android:scaleType="matrix" android:id="@+id/imageurl" /> </LinearLayout>
主介面對應的Java檔案
package com.example.test15; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.ImageView; import com.example.test15.picturemanage.PictureShowActivity; public class MainActivity extends Activity { private ImageView imageView; //手指按下的點為x1，手指離開螢幕的點為x2 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); imageView= findViewById(R.id.img_init); imageView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent=new Intent(MainActivity.this,PictureShowActivity.class); startActivity(intent); } }); } }
圖片放大對應的java檔案
package com.example.test15.picturemanage;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.widget.ImageView;
import com.example.test15.R;
import org.greenrobot.eventbus.EventBus;
import org.greenrobot.eventbus.Subscribe;
import org.greenrobot.eventbus.ThreadMode;
public class PictureShowActivity extends Activity {
private ImageView imageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_picture);
EventBus.getDefault().register(this);
imageView= findViewById(R.id.imageurl);
Bitmap bitmap=BitmapFactory.decodeResource(getResources(),R.drawable.girl);
imageView.setImageBitmap(bitmap);
}
@Subscribe(threadMode = ThreadMode.MAIN)
public void onUserEvent(ZooBus zoomBus) {
Log.d("zoomBus",zoomBus+"");
finish();
}
}
圖片的處理事件Java檔案
package com.example.test15.picturemanage;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.ScaleGestureDetector.OnScaleGestureListener;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewTreeObserver;
import android.widget.ImageView;
import org.greenrobot.eventbus.EventBus;
class ZoomImageView extends ImageView implements OnScaleGestureListener,
OnTouchListener, ViewTreeObserver.OnGlobalLayoutListener
{
private static final String TAG = ZoomImageView.class.getSimpleName();
public static final float SCALE_MAX = 4.0f;
private static final float SCALE_MID = 2.0f;
/**
* 初始化時的縮放比例，如果圖片寬或高大於螢幕，此值將小於0
*/
private float initScale = 1.0f;
private boolean once = true;
/**
* 用於存放矩陣的9個值
*/
private final float[] matrixValues = new float[9];
/**
* 縮放的手勢檢測
*/
private ScaleGestureDetector mScaleGestureDetector = null;
private final Matrix mScaleMatrix = new Matrix();
/**
* 用於雙擊檢測
*/
private GestureDetector mGestureDetector;
private boolean isAutoScale;
private int mTouchSlop;
private float mLastX;
private float mLastY;
private boolean isCanDrag;
private int lastPointerCount;
private boolean isCheckTopAndBottom = true;
private boolean isCheckLeftAndRight = true;
public ZoomImageView(Context context)
{
this(context, null);
}
public ZoomImageView(Context context, AttributeSet attrs)
{
super(context, attrs);
super.setScaleType(ScaleType.MATRIX);
mGestureDetector = new GestureDetector(context,
new SimpleOnGestureListener()
{
//單擊退出
@Override
public boolean onSingleTapConfirmed(MotionEvent e) {
EventBus.getDefault().post(new ZooBus());
return super.onSingleTapConfirmed(e);
}
//雙擊放大縮小
@Override
public boolean onDoubleTap(MotionEvent e)
{
if (isAutoScale == true) //首先判斷是否正在自動縮放,如果是直接返回true
return true;
float x = e.getX();
float y = e.getY();
Log.e("DoubleTap", getScale() + " , " + initScale);
//postDelayed每16ms執行一個AutoScaleRunnable方法
if (getScale() < SCALE_MID)
{
ZoomImageView.this.postDelayed(
new AutoScaleRunnable(SCALE_MID, x, y), 16);//如果獲得的縮放比例小於SCALE_MID,那麼就設定縮放比例為SCALE_MID
isAutoScale = true;
} else if (getScale() >= SCALE_MID
&& getScale() < SCALE_MAX)
{
ZoomImageView.this.postDelayed(
new AutoScaleRunnable(SCALE_MAX, x, y), 16);//如果獲得的縮放比例大於SCALE_MID並且小於SCALE_MAX，就設定縮放比例為SCALE_MAX
isAutoScale = true;
} else
{
ZoomImageView.this.postDelayed(
new AutoScaleRunnable(initScale, x, y), 16);//同理
isAutoScale = true;
}
return true;
}
});
mScaleGestureDetector = new ScaleGestureDetector(context, this); //縮放手勢檢測
this.setOnTouchListener(this); //這個藉口主要有onScale()、onScaleBegin()、onScaleEnd()方法
}
/**
* 自動縮放的任務
*
* @author zhy
*
*/
private class AutoScaleRunnable implements Runnable
{
static final float BIGGER = 1.07f;
static final float SMALLER = 0.93f;
private float mTargetScale;
private float tmpScale;
/**
* 縮放的中心
*/
private float x;
private float y;
/**
* 傳入目標縮放值，根據目標值與當前值，判斷應該放大還是縮小
*
* @param targetScale
*/
public AutoScaleRunnable(float targetScale, float x, float y)
{
this.mTargetScale = targetScale;
this.x = x;
this.y = y;
if (getScale() < mTargetScale)
{
tmpScale = BIGGER;
} else
{
tmpScale = SMALLER;
}
}
@Override
public void run()
{
// 進行縮放
mScaleMatrix.postScale(tmpScale, tmpScale, x, y);
checkBorderAndCenterWhenScale();//如果不用，圖片寬高大於螢幕時，圖片與螢幕間出現白邊；圖片小於螢幕，但是不居中。
setImageMatrix(mScaleMatrix);
final float currentScale = getScale();
// 如果值在合法範圍內，繼續縮放
if (((tmpScale > 1f) && (currentScale < mTargetScale))
|| ((tmpScale < 1f) && (mTargetScale < currentScale)))
{
Log.d("合理範圍",currentScale+" "+mTargetScale+" "+tmpScale);
ZoomImageView.this.postDelayed(this, 16);
} else
// 設定為目標的縮放比例
{
Log.d("目標範圍","目標範圍"+currentScale+" "+mTargetScale);
final float deltaScale = mTargetScale / currentScale;
Log.d("deltaScale",deltaScale+" ");
mScaleMatrix.postScale(deltaScale, deltaScale, x, y);
checkBorderAndCenterWhenScale();
setImageMatrix(mScaleMatrix);
isAutoScale = false;
}
}
}
//進行縮放，返回值代表縮放事件是否已經被處理
@SuppressLint("NewApi")
@Override
public boolean onScale(ScaleGestureDetector detector)
{
Log.d("scale","scale");
float scale = getScale();//當前已經縮放的縮放比例
float scaleFactor = detector.getScaleFactor();//通過手勢檢測檢測到的縮放比例
if (getDrawable() == null)
return true;
/**
* 縮放的範圍控制
*/
if ((scale < SCALE_MAX && scaleFactor > 1.0f)
|| (scale > initScale && scaleFactor < 1.0f))
{
/**
* 最大值最小值判斷
*/
if (scaleFactor * scale < initScale)
{
scaleFactor = initScale / scale;
}
if (scaleFactor * scale > SCALE_MAX)
{
scaleFactor = SCALE_MAX / scale;
}
/**
* 設定縮放比例
*/
mScaleMatrix.postScale(scaleFactor, scaleFactor,
detector.getFocusX(), detector.getFocusY());
checkBorderAndCenterWhenScale();
setImageMatrix(mScaleMatrix);
}
return true;
}
/**
* 在縮放時，進行圖片顯示範圍的控制
*/
private void checkBorderAndCenterWhenScale()
{
RectF rect = getMatrixRectF();
float deltaX = 0;
float deltaY = 0;
int width = getWidth();
int height = getHeight();
// 如果寬或高大於螢幕，則控制範圍
if (rect.width() >= width)
{
if (rect.left > 0)
{
deltaX = -rect.left;
}
if (rect.right < width)
{
deltaX = width - rect.right;
}
}
if (rect.height() >= height)
{
if (rect.top > 0)
{
deltaY = -rect.top;
}
if (rect.bottom < height)
{
deltaY = height - rect.bottom;
}
}
// 如果寬或高小於螢幕，則讓其居中
if (rect.width() < width)
{
deltaX = width * 0.5f - rect.right + 0.5f * rect.width();
}
if (rect.height() < height)
{
deltaY = height * 0.5f - rect.bottom + 0.5f * rect.height();
}
Log.e(TAG, "deltaX = " + deltaX + " , deltaY = " + deltaY);
mScaleMatrix.postTranslate(deltaX, deltaY); //deltaX大於0表示向右,deltaY大於0表示向下
}
/**
* 根據當前圖片的Matrix獲得圖片的範圍
*
* @return
*/
private RectF getMatrixRectF()
{
Matrix matrix = mScaleMatrix;
RectF rect = new RectF();
Drawable d = getDrawable();
if (null != d)
{
rect.set(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
matrix.mapRect(rect);
}
return rect;
}
@Override
public boolean onScaleBegin(ScaleGestureDetector detector)
{
return true;
}
@Override
public void onScaleEnd(ScaleGestureDetector detector)
{
}
//OnTouchListener介面方法
@Override
public boolean onTouch(View v, MotionEvent event)
{
if (mGestureDetector.onTouchEvent(event))
return true;
// mGestureDetector.onTouchEvent(event);
mScaleGestureDetector.onTouchEvent(event);
float x = 0, y = 0;
// 拿到觸控點的個數
final int pointerCount = event.getPointerCount();
// 得到多個觸控點的x與y均值
for (int i = 0; i < pointerCount; i++)
{
x += event.getX(i);
y += event.getY(i);
}
x = x / pointerCount;
y = y / pointerCount;
/**
* 每當觸控點發生變化時，重置mLasX , mLastY
*/
if (pointerCount != lastPointerCount)
{
isCanDrag = false;
mLastX = x;
mLastY = y;
}
lastPointerCount = pointerCount;
RectF rectF = getMatrixRectF();
switch (event.getAction())
{
// case MotionEvent.ACTION_DOWN:
// if (rectF.width() > getWidth() || rectF.height() > getHeight())
// {
// getParent().requestDisallowInterceptTouchEvent(true);
// }
// break;
case MotionEvent.ACTION_MOVE:
// if (rectF.width() > getWidth() || rectF.height() > getHeight())
// {
// getParent().requestDisallowInterceptTouchEvent(true);
// }
Log.e(TAG, "ACTION_MOVE");
float dx = x - mLastX;
float dy = y - mLastY;
if (!isCanDrag)
{
isCanDrag = isCanDrag(dx, dy);
}
if (isCanDrag)
{
if (getDrawable() != null)
{
// if (getMatrixRectF().left == 0 && dx > 0)
// {
// getParent().requestDisallowInterceptTouchEvent(false);
// }
//
// if (getMatrixRectF().right == getWidth() && dx < 0)
// {
// getParent().requestDisallowInterceptTouchEvent(false);
// }
isCheckLeftAndRight = isCheckTopAndBottom = true;
// 如果寬度小於螢幕寬度，則禁止左右移動
if (rectF.width() < getWidth())
{
dx = 0;
isCheckLeftAndRight = false;
}
// 如果高度小雨螢幕高度，則禁止上下移動
if (rectF.height() < getHeight())
{
dy = 0;
isCheckTopAndBottom = false;
}
mScaleMatrix.postTranslate(dx, dy);
checkMatrixBounds();
setImageMatrix(mScaleMatrix);
}
}
mLastX = x;
mLastY = y;
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
Log.e(TAG, "ACTION_UP");
lastPointerCount = 0;
break;
}
return true;
}
/**
* 獲得當前的縮放比例
*
* @return
*/
public final float getScale()
{
mScaleMatrix.getValues(matrixValues);
// Log.d("mscale_x", matrixValues[Matrix.MSCALE_X]+ "");
// Log.d("mscale_y",matrixValues[Matrix.MSCALE_Y]+"");
return matrixValues[Matrix.MSCALE_X]; //matrixValues[Matrix.MSCALE_X]與matrixValues[Matrix.MSCALE_Y]是一樣的
}
@Override
protected void onAttachedToWindow()
{
super.onAttachedToWindow();
getViewTreeObserver().addOnGlobalLayoutListener(this);
}
@SuppressWarnings("deprecation")
@Override
protected void onDetachedFromWindow()
{
super.onDetachedFromWindow();
getViewTreeObserver().removeGlobalOnLayoutListener(this);
}
//根據圖片的寬和高以及螢幕的寬和高，對圖片進行縮放以及移動至螢幕的中心。如果圖片很小，那就正常顯示，不放大了~
@Override
public void onGlobalLayout()
{
if (once)
{
Drawable d = getDrawable();
if (d == null)
return;
Log.e(TAG, d.getIntrinsicWidth() + " , " + d.getIntrinsicHeight());
int width = getWidth();
int height = getHeight();
// 拿到圖片的寬和高
int dw = d.getIntrinsicWidth();
int dh = d.getIntrinsicHeight();
float scale = 1.0f;
// 如果圖片的寬或者高大於螢幕，則至螢幕的寬或者高
if (dw > width && dh <= height)
{
scale = width * 1.0f / dw;
}
if (dh > height && dw <= width)
{
scale = height * 1.0f / dh;
}
// 如果寬和高都大於螢幕，則讓其按按比例適應螢幕大小
if (dw > width && dh > height)
{
scale = Math.min(width * 1.0f / dw, height * 1.0f / dh);
}
initScale = scale;
Log.e(TAG, "initScale = " + initScale);
mScaleMatrix.postTranslate((width - dw) / 2, (height - dh) / 2);
mScaleMatrix.postScale(scale, scale, getWidth() / 2,
getHeight() / 2);
// 圖片移動至螢幕中心
setImageMatrix(mScaleMatrix);
once = false;
}
}
/**
* 移動時，進行邊界判斷，主要判斷寬或高大於螢幕的
*/
private void checkMatrixBounds()
{
RectF rect = getMatrixRectF();
float deltaX = 0, deltaY = 0;
final float viewWidth = getWidth();
final float viewHeight = getHeight();
// 判斷移動或縮放後，圖片顯示是否超出螢幕邊界
if (rect.top > 0 && isCheckTopAndBottom)
{
deltaY = -rect.top;
}
if (rect.bottom < viewHeight && isCheckTopAndBottom)
{
deltaY = viewHeight - rect.bottom;
}
if (rect.left > 0 && isCheckLeftAndRight)
{
deltaX = -rect.left;
}
if (rect.right < viewWidth && isCheckLeftAndRight)
{
deltaX = viewWidth - rect.right;
}
mScaleMatrix.postTranslate(deltaX, deltaY);
}
/**
* 是否是推動行為
*
* @param dx
* @param dy
* @return
*/
private boolean isCanDrag(float dx, float dy)
{
return Math.sqrt((dx * dx) + (dy * dy)) >= mTouchSlop;
}
}
package com.example.test15.picturemanage;
public class ZooBus {
}