我想要实施什么？
使用ViewPager的图片的图库。我选择这个选项是因为图像之间的平滑过渡（我使用的是ImageView），它很好并且很容易实现。
我的问题究竟是什么？
我已经能够实现所有这些但缩放功能无效。我可以在 LogCat 中看到它是如何打印的 ZOOM （代码在帖子的末尾），但图像没有放大。关于以下代码的几点说明：
ImageViewHelperURL.setUrlDrawable((ImageView) img, url, R.drawable.no_image);我正在使用UrlImageViewHelper以异步方式从网络下载图片。api.getListUrls()这是一个ArrayList，我有图片网址。我也试过使用R.drawable中的ImageView而不是下载图像
import android.content.Context;
import android.content.Intent;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.os.Bundle;
import android.support.v4.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.Menu;
import android.support.v4.view.MenuItem;
import android.support.v4.view.ViewPager;
import android.util.FloatMath;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MenuInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.Toast;
public class Slide extends FragmentActivity {
private ViewPager mPager;
public static Api api;
public static int POSITION;
public static ActionBar topbar;
public static Context ctx;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment);
ctx = Slide.this;
POSITION = 0;
topbar = getSupportActionBar();
/* get portadas */
api = new Api();
api.getUrlsFromAPI();
topbar.setDisplayShowHomeEnabled(false);
topbar.setDisplayShowTitleEnabled(true);
mPager = (ViewPager) findViewById(R.id.pager);
mPager.setAdapter(new TestAdapter(getSupportFragmentManager()));
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
mPager.setCurrentItem(POSITION);
}
static final class TestAdapter extends FragmentPagerAdapter {
public TestAdapter(FragmentManager fm) {
super(fm);
}
@Override
public int getCount() {
return api.getListUrls().size();
}
@Override
public Fragment getItem(int position) {
TestFragment f = new TestFragment();
f.url = api.getListUrls().get(position).getUrl();
f.position = position;
return f;
}
}
public static class TestFragment extends Fragment {
String url = "";
Integer position = 0;
public TestFragment() {
setRetainInstance(true);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
ImageView img = new ImageView(getActivity());
img.setPadding(6, 6, 6, 6) ;
img.setLayoutParams(new Gallery.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)) ;
ImageViewHelperURL.setUrlDrawable((ImageView) img, url, R.drawable.no_image) ;
img.setOnTouchListener(new OnTouchListener() {
private static final String TAG = "SlideImageView";
// 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;
int mode = NONE;
// Remember some things for zooming
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
// 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 == DRAG) {
// ...
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x,
event.getY() - start.y);
} else if (mode == ZOOM) {
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale = newDist / oldDist;
Log.d(TAG, "ZOOOOOOOM: " + scale);
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
view.setImageMatrix(matrix);
return true; // indicate event was handled
}
/** Show an event in the LogCat view, for debugging */
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());
}
/** 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);
}
});
return img;
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
return super.onOptionsItemSelected(item);
}
}
}
我已经尝试过以下教程但没有成功：
答案 0 :(得分：9)
如果您想使用带有ImageView的矩阵来转换图像，则需要将scale type更改为ScaleType.Matrix，否则将无效。默认比例类型为ScaleType.FIT_CENTER，因此它将忽略矩阵。
关于您的原始任务，如果您正常工作，您可能会发现ImageView上的触摸手势会干扰ViewPager的滚动。您肯定会遇到支持单触式拖动的问题，因为这与自然的ViewPager滑动动作直接对应，可以转到下一个视图。