android 监听两指缩放,Android两根手指放大/缩小不起作用

我找到了这个

How to enable the (two finger) zoom in/out feature for an image in android

在日志中,我看到它正在运行,但是图像没有改变,我在做什么错？

这是我的XML

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context=".ViewImage" >

android:id="@+id/myimage"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:layout_alignParentLeft="true"

android:layout_alignParentRight="true"

android:layout_alignParentTop="true"

android:layout_alignParentBottom="true" />

这是我的代码

public class ViewImage extends Activity implements OnTouchListener {

private SQLiteDatabase qdb;

ImageView myimage;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_view_image);

myimage = (ImageView) findViewById(R.id.myimage);

DB db = new DB(this);

qdb = db.getReadableDatabase();

Bundle b = getIntent().getExtras();

int img_id = b.getInt("img_id");

Cursor c = qdb.rawQuery("select name, comment from photos where _id="+img_id+"", null);

if(c.moveToFirst()){

String img_name = c.getString(c.getColumnIndex("name"));

String img_comment = c.getString(c.getColumnIndex("comment"));

File directory = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM), "NNCam");

String resPath = directory.getPath();

Bitmap imgComment = getPoster(img_comment, resPath+img_name);

saveImage(resPath+"/Temp", img_name, imgComment);

myimage.setImageBitmap(BitmapFactory.decodeFile(resPath+img_name));

myimage.setOnTouchListener(this);

}

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.view_image, menu);

return true;

}

public void saveImage(String path, String imgname, Bitmap image){

try{

FileOutputStream fos = new FileOutputStream(path+imgname);

BufferedOutputStream stream = new BufferedOutputStream(fos);

image.compress(CompressFormat.JPEG, 100, stream);

stream.flush();

stream.close();

}

catch(FileNotFoundException e){

}

catch(IOException e){

}

}

private static Bitmap getPoster(String yazi, String resPath) {

Bitmap background = BitmapFactory.decodeFile(resPath).copy(Bitmap.Config.ARGB_8888, true);;

Canvas canvas = new Canvas(background);

Paint paint = new Paint();

paint.setAntiAlias(true);

paint.setColor(Color.WHITE);

paint.setStyle(Style.FILL);

paint.setShadowLayer(2.0f, 1.0f, 1.0f, Color.BLACK);

float fontSize = background.getHeight()/30; //You'll have to define a way to find a size that fits, or just use a constant size.

paint.setTextSize(fontSize);

int y = (int) background.getHeight() - 100;

for(String line: yazi.split("

")){

canvas.drawText(line, ((background.getWidth() - paint.measureText(line)) / 2), y, paint);

y-=paint.ascent()+paint.descent()-5;

}

return background;

}

private static final String TAG = "Touch";

//These matrices will be used to move and zoom image

Matrix matrix = new Matrix();

Matrix savedMatrix = new Matrix();

// We can be in one of these 3 states

static final int NONE = 0;

static final int DRAG = 1;

static final int ZOOM = 2;

static final int DRAW =3;

int mode = NONE;

// Remember some things for zooming

PointF start = new PointF();

PointF mid = new PointF();

float oldDist = 1f;

// Limit zoomable/pannable image

private float[] matrixValues = new float[9];

private float maxZoom;

private float minZoom;

private float height;

private float width;

private RectF viewRect;

/************ touch events functions **************

@Override

public void onWindowFocusChanged(boolean hasFocus) {

super.onWindowFocusChanged(hasFocus);

if(hasFocus){ init(); }

}

private void init() {

maxZoom = 4;

minZoom = 0.25f;

height = myimage.getDrawable().getIntrinsicHeight()+20;

width = myimage.getDrawable().getIntrinsicWidth()+20;

viewRect = new RectF(0, 0, myimage.getWidth()+20, myimage.getHeight()+20);

}

/************touch events for image Moving, panning and zooming ***********///

public boolean onTouch(View v, MotionEvent event) {

// Dump touch event to log

dumpEvent(event);

// Handle touch events here...

switch (event.getAction() & MotionEvent.ACTION_MASK) {

case MotionEvent.ACTION_DOWN:

savedMatrix.set(matrix);

start.set(event.getX(), event.getY());

Log.d(TAG, "mode=DRAG");

mode = DRAG;

break;

case MotionEvent.ACTION_POINTER_DOWN:

oldDist = spacing(event);

Log.d(TAG, "oldDist=" + oldDist);

if (oldDist > 10f) {

savedMatrix.set(matrix);

midPoint(mid, event);

mode = ZOOM;

Log.d(TAG, "mode=ZOOM");

}

break;

case MotionEvent.ACTION_UP:

case MotionEvent.ACTION_POINTER_UP:

mode = NONE;

Log.d(TAG, "mode=NONE");

break;

case MotionEvent.ACTION_MOVE:

if (mode == DRAW){ onTouchEvent(event);}

if (mode == DRAG) {

///code for draging..

}

else if (mode == ZOOM) {

float newDist = spacing(event);

Log.d(TAG, "newDist=" + newDist);

if (newDist > 10f) {

matrix.set(savedMatrix);

float scale = newDist / oldDist;

matrix.getValues(matrixValues);

float currentScale = matrixValues[Matrix.MSCALE_X];

// limit zoom

if (scale * currentScale > maxZoom) {

scale = maxZoom / currentScale;

}else if(scale * currentScale < minZoom){

scale = minZoom / currentScale;

}

matrix.postScale(scale, scale, mid.x, mid.y);

}

}

break;

}

myimage.setImageMatrix(matrix);

return true; // indicate event was handled

}

//*******************Determine the space between the first two fingers

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);

}

//************* Calculate the mid point of the first two fingers

private void midPoint(PointF point, MotionEvent event) {

float x = event.getX(0) + event.getX(1);

float y = event.getY(0) + event.getY(1);

point.set(x / 2, y / 2);

}

private void dumpEvent(MotionEvent event) {

String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",

"POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };

StringBuilder sb = new StringBuilder();

int action = event.getAction();

int actionCode = action & MotionEvent.ACTION_MASK;

sb.append("event ACTION_").append(names[actionCode]);

if (actionCode == MotionEvent.ACTION_POINTER_DOWN

|| actionCode == MotionEvent.ACTION_POINTER_UP) {

sb.append("(pid ").append(

action >> MotionEvent.ACTION_POINTER_ID_SHIFT);

sb.append(")");

}

sb.append("[");

for (int i = 0; i < event.getPointerCount(); i++) {

sb.append("#").append(i);

sb.append("(pid ").append(event.getPointerId(i));

sb.append(")=").append((int) event.getX(i));

sb.append(",").append((int) event.getY(i));

if (i + 1 < event.getPointerCount())

sb.append(";");

}

sb.append("]");

Log.d(TAG, sb.toString());

}

}