我发现了这个 如何在android中为图像启用（两指）放大/缩小功能
在日志中我看到它正在工作但图像没有改变，我做错了什么？
这是我的xml
<RelativeLayout 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"
tools:context=".ViewImage" >
<ImageView
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" />
</RelativeLayout>
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("\n")){
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());
}
}