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我想實現什麼？使用ViewPager的圖像庫+放大ImageViews
A gallery使用ViewPager的圖像。我選擇這個選項是因爲圖像之間的平滑過渡（我正在使用ImageView），它很好，很容易實現。
究竟是什麼問題？
我已經能夠實現所有這些但縮放無法正常工作。我可以在LogCat中看到它是如何打印的ZOOM（代碼位於文章末尾），但圖像未放大。只是下面的代碼幾點注意事項：
ImageViewHelperURL.setUrlDrawable((ImageView) img, url, R.drawable.no_image);我使用UrlImageViewHelper異步從網上下載的圖片。api.getListUrls()這是一個ArrayList，我有圖像網址。我試着使用也從R.drawable的ImageView的，而不是下載圖像
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); } } }
我已經嘗試沒有成功以下教程：
這個問題遲到了 - 但是如果你使用ViewPager作爲你的圖庫 - 你永遠不會回收所有這些片段，對吧？你只是不斷創造新的？ – user291701 2012-06-29 05:25:14
我想我正在回收它們。當你回到（前一個活動）時，這一個被毀壞？但我只是一個初學者，我不確定。 – 2012-06-29 14:36:53