我制作了一个应用程序，它从 url 下载图像（使用Universal Image Loader库）并将该图像显示在TouchImageView. 我使用 Touch Image View 来实现捏缩放功能。我按照本教程学习了如何使用 TouchImageView。
问题是，每当我放大由 Universal Image Loader 下载的图像并将另一个图像加载到 TouchImageView 中时，新图像都会被拉伸和扭曲。当之前的缩放图像通过缩小恢复到原始大小，然后加载新图像时，这个问题就解决了。
所以这个问题可以通过缩小加载的图像，然后加载新的图像来解决。但我不知道如何重置缩放，并且库不提供此功能。
我尝试使用最新版本的TouchImageView（包括重置图像功能），但较新的版本与它不兼容，UIL而且似乎本教程只使用了原始库中的一部分代码（很难正常工作）。
有谁知道如何重置放大TouchImageView？
**强文本**代码：
package com.hpubts50.hpubustracker;
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
Matrix 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;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 8f;
float[] m;
int viewWidth, viewHeight;
static final int CLICK = 3;
float saveScale = 1f;
protected float origWidth, origHeight;
int oldMeasuredWidth, oldMeasuredHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public TouchImageView(Context context) {
super(context);
sharedConstructing(context);
}
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix = new Matrix();
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(curr);
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float fixTransX = getFixDragTrans(deltaX, viewWidth, origWidth * saveScale);
float fixTransY = getFixDragTrans(deltaY, viewHeight, origHeight * saveScale);
matrix.postTranslate(fixTransX, fixTransY);
fixTrans();
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
}
public void setMaxZoom(float x) {
maxScale = x;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = detector.getScaleFactor();
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
if (origWidth * saveScale <= viewWidth || origHeight * saveScale <= viewHeight)
matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2, viewHeight / 2);
else
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
fixTrans();
return true;
}
}
void fixTrans() {
matrix.getValues(m);
float transX = m[Matrix.MTRANS_X];
float transY = m[Matrix.MTRANS_Y];
float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);
float fixTransY = getFixTrans(transY, viewHeight, origHeight * saveScale);
if (fixTransX != 0 || fixTransY != 0)
matrix.postTranslate(fixTransX, fixTransY);
}
float getFixTrans(float trans, float viewSize, float contentSize) {
float minTrans, maxTrans;
if (contentSize <= viewSize) {
minTrans = 0;
maxTrans = viewSize - contentSize;
} else {
minTrans = viewSize - contentSize;
maxTrans = 0;
}
if (trans < minTrans)
return -trans + minTrans;
if (trans > maxTrans)
return -trans + maxTrans;
return 0;
}
float getFixDragTrans(float delta, float viewSize, float contentSize) {
if (contentSize <= viewSize) {
return 0;
}
return delta;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
viewWidth = MeasureSpec.getSize(widthMeasureSpec);
viewHeight = MeasureSpec.getSize(heightMeasureSpec);
//
// Rescales image on rotation
//
if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight || viewWidth == 0 || viewHeight == 0)
return;
oldMeasuredHeight = viewHeight;
oldMeasuredWidth = viewWidth;
if (saveScale == 1) {
// Fit to screen.
float scale;
Drawable drawable = getDrawable();
if (drawable == null || drawable.getIntrinsicWidth() == 0 || drawable.getIntrinsicHeight() == 0)
return;
int bmWidth = drawable.getIntrinsicWidth();
int bmHeight = drawable.getIntrinsicHeight();
Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);
float scaleX = (float) viewWidth / (float) bmWidth;
float scaleY = (float) viewHeight / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
// Center the image
float redundantYSpace = (float) viewHeight - (scale * (float) bmHeight);
float redundantXSpace = (float) viewWidth - (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = viewWidth - 2 * redundantXSpace;
origHeight = viewHeight - 2 * redundantYSpace;
setImageMatrix(matrix);
}
fixTrans();
}
}
PhotoActivity.java
package com.hpubts50.hpubustracker;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.Typeface;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.assist.DiscCacheUtil;
import com.nostra13.universalimageloader.core.assist.FailReason;
import com.nostra13.universalimageloader.core.assist.ImageLoadingListener;
import com.nostra13.universalimageloader.core.assist.ImageLoadingProgressListener;
public class PhotoActivity extends ActionBarActivity implements OnClickListener {
private Button btn_insideView, btn_outsideView, btn_resetZoom;
private ImageView img_busIcon;
private TouchImageView img_pictureViewer;
private TextView tv_busName, tv_busNo, tv_cameraStatus;
private String BusID = null;
private String BusName = null;
private ImageLoaderConfiguration config;
private ImageLoader imageLoader;
private DisplayImageOptions options;
private String url;
private static String SERVER_PATH = "http://hpubts.hpuiitshimla.org/images/";
private ProgressBar pb_loading;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_photo);
// Initialize Views
initializeViews();
// Get BusID from Bundle
Bundle gotPhotoBundle = getIntent().getExtras();
BusID = gotPhotoBundle.getString("BusID");
BusName = gotPhotoBundle.getString("BusName");
// Setting Bus Information
if (BusName.toLowerCase().equals("airavat")) {
img_busIcon.setImageResource(R.drawable.airavat);
} else if (BusName.toLowerCase().equals("alaknanda")) {
img_busIcon.setImageResource(R.drawable.alaknanda);
} else if (BusName.toLowerCase().equals("chaitanya")) {
img_busIcon.setImageResource(R.drawable.chaitanya);
} else if (BusName.toLowerCase().equals("garud")) {
img_busIcon.setImageResource(R.drawable.garud);
} else if (BusName.toLowerCase().equals("nandi")) {
img_busIcon.setImageResource(R.drawable.nandi);
} else if (BusName.toLowerCase().equals("neela")) {
img_busIcon.setImageResource(R.drawable.neela);
} else if (BusName.toLowerCase().equals("pushpak")) {
img_busIcon.setImageResource(R.drawable.pushpak);
}
tv_busName.setText(BusName);
tv_busNo.setText(BusID);
tv_cameraStatus.setText("Back Cam");
// Photo Loading Initializing
config = new ImageLoaderConfiguration.Builder(getApplicationContext()).build();
ImageLoader.getInstance().init(config);
imageLoader = ImageLoader.getInstance();
options = new DisplayImageOptions.Builder().resetViewBeforeLoading(true).cacheOnDisc(true).showImageOnFail(R.drawable.ic_action_warning).build();
// Start Back Photo Download
pb_loading.setProgress(0);
pb_loading.setVisibility(View.VISIBLE);
startPhotoDownload(img_pictureViewer, SERVER_PATH + BusID + "_back.jpg");
}
private void initializeViews() {
btn_insideView = (Button) findViewById(R.id.btn_insideView);
btn_outsideView = (Button) findViewById(R.id.btn_outsideView);
btn_resetZoom = (Button) findViewById(R.id.btn_resetZoom);
tv_busName = (TextView) findViewById(R.id.txt_busname);
tv_busNo = (TextView) findViewById(R.id.txt_busno);
tv_cameraStatus = (TextView) findViewById(R.id.txt_camera_status);
img_pictureViewer = (TouchImageView) findViewById(R.id.img_photoViewer);
img_busIcon = (ImageView) findViewById(R.id.img_busicon);
pb_loading = (ProgressBar) findViewById(R.id.pb_loading);
btn_insideView.setOnClickListener(this);
btn_outsideView.setOnClickListener(this);
btn_resetZoom.setOnClickListener(this);
// Set Font Type
setTypeface(btn_insideView);
setTypeface(btn_outsideView);
setTypeface(btn_resetZoom);
setTypeface(tv_busName);
setTypeface(tv_busNo);
setTypeface(tv_cameraStatus);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.photo, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_insideView:
url = SERVER_PATH + BusID + "_front.jpg";
tv_cameraStatus.setText("Front Cam");
break;
case R.id.btn_outsideView:
url = SERVER_PATH + BusID + "_back.jpg";
tv_cameraStatus.setText("Back Cam");
break;
case R.id.btn_resetZoom:
break;
}
// img_pictureViewer
pb_loading.setProgress(0);
pb_loading.setVisibility(View.VISIBLE);
startPhotoDownload(img_pictureViewer, url);
}
private void startPhotoDownload(ImageView img_Viewer, String completeUrl) {
imageLoader.displayImage(completeUrl, img_Viewer, options, new ImageLoadingListener() {
@Override
public void onLoadingStarted(String imageUri, View view) {
DiscCacheUtil.removeFromCache(imageUri, ImageLoader.getInstance().getDiscCache());
}
@Override
public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
pb_loading.setVisibility(View.INVISIBLE);
Toast.makeText(getApplicationContext(), "Image Loading Failed", Toast.LENGTH_SHORT).show();
}
@Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
pb_loading.setVisibility(View.INVISIBLE);
}
@Override
public void onLoadingCancelled(String imageUri, View view) {
}
}, new ImageLoadingProgressListener() {
@Override
public void onProgressUpdate(String imageUri, View view, int current, int total) {
pb_loading.setMax(total);
pb_loading.setProgress(current);
}
});
}
// Method to set Font Type to Compact
private void setTypeface(TextView textView) {
Typeface custom_font = Typeface.createFromAsset(getAssets(), "fonts/compact.ttf");
textView.setTypeface(custom_font);
}
private void setTypeface(Button button) {
Typeface custom_font = Typeface.createFromAsset(getAssets(), "fonts/compact.ttf");
button.setTypeface(custom_font);
}
}