Android自訂View實現圖片顯示，並實現縮放、拖拽、切換功能

這裡貼三個檔案的原始碼，第一個是main.java

package com.example.test;import java.util.ArrayList;import java.util.List;import com.example.test.MyXZ;import com.example.test.R;import com.example.test.ZoomListener;import com.example.test.test;import com.example.test.R.drawable;import com.example.test.R.id;import com.example.test.R.layout;import com.example.test.ZoomListener.Swiper;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Bundle;import android.view.View;public class main extends Activity {/** Called when the activity is first created. */private Bitmap mBitmap;private List<Bitmap> mlist;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);Bitmap m1=BitmapFactory.decodeResource(getResources(), R.drawable.m1);Bitmap m2=BitmapFactory.decodeResource(getResources(), R.drawable.m2);Bitmap m3=BitmapFactory.decodeResource(getResources(), R.drawable.m3);Bitmap m4=BitmapFactory.decodeResource(getResources(), R.drawable.m4);Bitmap m5=BitmapFactory.decodeResource(getResources(), R.drawable.m5);Bitmap m6=BitmapFactory.decodeResource(getResources(), R.drawable.m6);Bitmap m7=BitmapFactory.decodeResource(getResources(), R.drawable.m7);Bitmap m8=BitmapFactory.decodeResource(getResources(), R.drawable.m8);mlist=new ArrayList<Bitmap>();mlist.add(m1);mlist.add(m2);mlist.add(m3);mlist.add(m4);mlist.add(m5);mlist.add(m6);mlist.add(m7);mlist.add(m8);final test tt=(test) this.getApplication();this.setContentView(R.layout.activity_main);MyXZ iv=(MyXZ) findViewById(R.id.myXZ1);iv.setImage(mlist.get(tt.getCurr()));iv.update();ZoomListener zl=new ZoomListener();Swiper swp=new Swiper(){@Overridepublic void Swipe(View v, float length) {// TODO 自動產生的方法存根if(Math.abs(length)>20){int Curr=tt.getCurr();int i=length>0?1:-1;if(Curr+i<0){Curr=mlist.size()-1;}else if(Curr+i>=mlist.size()){Curr=0;}else{Curr+=i;}tt.setCurr(Curr);((MyXZ)v).setImage(mlist.get(Curr));}}};zl.setSwp(swp);iv.setOnTouchListener(zl);} @Overrideprotected void onDestroy() {super.onDestroy();if (mBitmap != null){mBitmap.recycle();}}}

第二個未見為ZoomListenner.java

package com.example.test;import android.graphics.PointF;import android.util.FloatMath;import android.util.Log;import android.view.MotionEvent;import android.view.View;import android.view.View.OnTouchListener;public class ZoomListener implements OnTouchListener {float Ospace;PointF start = new PointF(0, 0);String Mode;private Swiper swp;@Overridepublic boolean onTouch(View v, MotionEvent event) {// TODO 自動產生的方法存根switch (event.getAction() & MotionEvent.ACTION_MASK) {case MotionEvent.ACTION_DOWN:start.set(event.getX(), event.getY());Log.i("info", start.x + ":" + start.y);Mode = "DRAG";break;case MotionEvent.ACTION_POINTER_DOWN:Ospace = spacing(event);Mode = "ZOOM";Log.i("info", "原始面積" + Ospace);break;case MotionEvent.ACTION_UP:case MotionEvent.ACTION_POINTER_UP:Mode = "NONE";if(((MyXZ) v).getZoom() == 1){float sx = start.x - event.getX();float sy = start.y - event.getY();if (Math.abs(sx) > Math.abs(sy)) {swp.Swipe(v, sx/10);}}start.set(event.getX(), event.getY());break;case MotionEvent.ACTION_MOVE:if (Mode == "DRAG") {if (((MyXZ) v).getZoom() > 1) {float sx = start.x - event.getX();float sy = start.y - event.getY();if(Math.sqrt(sx*sx+sy*sy)>20){((MyXZ) v).setPan((int) (start.x - event.getX()),(int) (start.y - event.getY()));Log.i("info", "平移：" + ((MyXZ) v).getPan().x + ":"+ ((MyXZ) v).getPan().y);start.set(event.getX(), event.getY());}} } else if (Mode == "ZOOM") {float nspace = spacing(event);float zoom = 1 + (nspace - Ospace) / Ospace;if(Math.abs(nspace - Ospace)>3){((MyXZ) v).setZoom(zoom);Log.i("Info", "縮放為：" + ((MyXZ) v).getZoom());Ospace=nspace;}}break;}return true;}private float spacing(MotionEvent event) {float x = event.getX(0) - event.getX(1);float y = event.getY(0) - event.getY(1);return FloatMath.sqrt(x * x + y * y);}public Swiper getSwp() {return swp;}public void setSwp(Swiper swp) {this.swp = swp;}public interface Swiper {public void Swipe(View v, float length);}}

第三個為自訂的View MyXZ.java

package com.example.test;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.Point;import android.graphics.Rect;import android.util.AttributeSet;import android.view.View;public class MyXZ extends View {private final Paint mPaint = new Paint(Paint.FILTER_BITMAP_FLAG);private final Rect SrcRect = new Rect();private final Rect DstRect = new Rect();private float RecentZoom = 1;private float Zoom = 1;private Point Pan = new Point(0, 0);private Bitmap mBitmap;public MyXZ(Context context, AttributeSet attrs) {super(context, attrs);}@Overrideprotected void onDraw(Canvas canvas) {if (mBitmap != null) {UpdateRZ();canvas.drawBitmap(mBitmap, SrcRect, DstRect, mPaint);}}private void UpdateRZ() {if (mBitmap != null) {float bw = mBitmap.getWidth();float bh = mBitmap.getHeight();float Sw = getWidth();float Sh = getHeight();if (bw * (Sh / bh) <= Sw) {RecentZoom = Sh / bh;}if (bh * (Sw / bw) <= Sh) {RecentZoom = Sw / bw;}int DesX = (int) Math.min(mBitmap.getWidth() * RecentZoom* getZoom(), getWidth());int DesY = (int) Math.min(mBitmap.getHeight() * RecentZoom* getZoom(), getHeight());int ResX = Math.round(DesX / RecentZoom / getZoom());int ResY = Math.round(DesY / RecentZoom / getZoom());if (Pan.x + (bw - ResX) / 2 < 0) {Pan.x = -((int) (bw - ResX) / 2);}if (Pan.y + (bh - ResY) / 2 < 0) {Pan.y = -((int) ((bh - ResY) / 2));}if (ResX + (Pan.x + (bw - ResX) / 2) > bw) {Pan.x = (int) ((bw - ResX) / 2);}if (ResY + Pan.y + (bh - ResY) / 2 > bh) {Pan.y = (int) ((bh - ResY) / 2);}SrcRect.left = (int) (Pan.x + (bw - ResX) / 2);SrcRect.top = (int) (Pan.y + (bh - ResY) / 2);SrcRect.right = (int) (ResX + (Pan.x + (bw - ResX) / 2));SrcRect.bottom = (int) (ResY + Pan.y + (bh - ResY) / 2);DstRect.left = (getWidth() - DesX) / 2;DstRect.right = (getWidth() - DesX) / 2 + DesX;DstRect.top = (getHeight() - DesY) / 2;DstRect.bottom = (getHeight() - DesY) / 2 + DesY;}}public void setPan(int x, int y) {Pan.x += x * getZoom() * RecentZoom;Pan.y += y * getZoom() * RecentZoom;update();}public Point getPan() {return Pan;}public void update() {UpdateRZ();invalidate();}public void setImage(Bitmap bitmap) {mBitmap = bitmap;UpdateRZ();invalidate();}@Overrideprotected void onLayout(boolean changed, int left, int top, int right,int bottom) {super.onLayout(changed, left, top, right, bottom);UpdateRZ();}public float getZoom() {return Zoom;}public void setZoom(float zoom) {if (RecentZoom < 1) {if (zoom * Zoom >= 1) {Zoom *= zoom;if (Zoom >= 1/ RecentZoom) {Zoom = 1/ RecentZoom;}} else {Zoom = 1;}} else {Zoom = 1;}update();}}

詳細的就不多說了，有興趣想瞭解詳細內容的，可以到我的個人網站下載源碼查看：http://www.nuatar.com/Article.aspx?id=d69f35891c0840278bed7a2e12b7b050

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