如何创建动态文件视图？

Question

您好，我希望创建动态文件视图图库图像，但我不知道如何创建动态文件视图......请帮助我......给我你的建议......

这是我的画廊视图当前代码：

package ImageViewExample.ImageViewExample;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
//import android.widget.GridView;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;

public class ImageViewExample extends Activity {
  /** Called when the activity is first created. */
  private Cursor imagecursor, actualimagecursor;
  private int image_column_index, actual_image_column_index;
  Gallery imagegrid;
  private int count;
  @Override
  public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        init_phone_image_grid();
  }
  private void init_phone_image_grid() {
        String[] img = { MediaStore.Images.Thumbnails._ID };
        imagecursor = managedQuery(
  MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, img, null,
  null, MediaStore.Images.Thumbnails.IMAGE_ID + "");
        image_column_index = imagecursor
  .getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID);
        count = imagecursor.getCount();
        imagegrid = (Gallery) findViewById(R.id.PhoneImageGrid);
        imagegrid.setAdapter(new ImageAdapter(getApplicationContext()));
        imagegrid.setOnItemClickListener(new OnItemClickListener() {
              public void onItemClick(AdapterView parent, View v,
   int position, long id) {
                    System.gc();
                    String[] proj = { MediaStore.Images.Media.DATA };
                    actualimagecursor = managedQuery(
    MediaStore.Images.Media.EXTERNAL_CONTENT_URI, proj,
    null, null, null);
                    actual_image_column_index = actualimagecursor
    .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
                    actualimagecursor.moveToPosition(position);
                    String i = actualimagecursor.getString(actual_image_column_index);
                    System.gc();
                    Intent intent = new Intent(getApplicationContext(),     
     ViewImage.class);
                    intent.putExtra("filename", i);
                    startActivity(intent);
              }
        });
       }


  public class ImageAdapter extends BaseAdapter {
        private             Context mContext;
        public ImageAdapter(Context c) {
              mContext = c;
        }
        public int getCount() {
              return count;
        }
        public Object getItem(int position) {
              return position;
        }
        public long getItemId(int position) {
              return position;
        }
        public View getView(int position,View convertView,ViewGroup parent) {
              System.gc();
              ImageView i = new ImageView(mContext.getApplicationContext());
              if (convertView == null) {
                    imagecursor.moveToPosition(position);
                    int id = imagecursor.getInt(image_column_index);
                    i.setImageURI(Uri.withAppendedPath(
      MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, ""
     + id));
                    i.setScaleType(ImageView.ScaleType.CENTER_CROP);
                    i.setLayoutParams(new Gallery.LayoutParams(110,110));
              }
              else {
                    i = (ImageView) convertView;
              }
              return i;
        }
    }
    }

这是我的 Xml 编码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Gallery xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/PhoneImageGrid" 
android:layout_width="fill_parent"
android:layout_height="fill_parent" 
android:numColumns="auto_fit"
android:verticalSpacing="10dp" 
android:horizontalSpacing="10dp"
android:columnWidth="90dp" 
android:stretchMode="columnWidth"
android:spacing="16dp"
 />
</LinearLayout>

log cat 错误：

04-25 23:06:14.329: INFO/Process(391): Sending signal. PID: 391 SIG: 9
04-25 23:06:14.389: INFO/ActivityManager(63): Process 
ImageViewExample.ImageViewExample (pid 391) has died.
04-25 23:06:14.800: WARN/InputManagerService(63): Window already focused, ignoring 
focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@43fdc730
04-25 23:06:26.009: DEBUG/AndroidRuntime(403): >>>>>>>>>>>>>> AndroidRuntime START 
<<<<<<<<<<<<<<
04-25 23:06:26.019: DEBUG/AndroidRuntime(403): CheckJNI is ON
04-25 23:06:26.580: DEBUG/AndroidRuntime(403): --- registering native functions ---
04-25 23:06:28.259: DEBUG/AndroidRuntime(403): Shutting down VM
04-25 23:06:28.300: DEBUG/dalvikvm(403): Debugger has detached; object registry had 1 
entries
04-25 23:06:28.329: INFO/AndroidRuntime(403): NOTE: attach of thread 'Binder Thread 
#3' failed
04-25 23:06:29.389: DEBUG/AndroidRuntime(411): >>>>>>>>>>>>>> AndroidRuntime START 
<<<<<<<<<<<<<<
04-25 23:06:29.389: DEBUG/AndroidRuntime(411): CheckJNI is ON
04-25 23:06:29.839: DEBUG/AndroidRuntime(411): --- registering native functions ---
04-25 23:06:31.359: INFO/ActivityManager(63): Starting activity: Intent { 
act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 
cmp=ImageViewExample.ImageViewExample/.ImageViewExample }
04-25 23:06:31.610: DEBUG/AndroidRuntime(411): Shutting down VM
04-25 23:06:31.730: DEBUG/dalvikvm(411): Debugger has detached; object registry had 1 
entries
04-25 23:06:31.786: INFO/AndroidRuntime(411): NOTE: attach of thread 'Binder Thread 
#3' failed
04-25 23:06:32.019: INFO/ActivityManager(63): Start proc 
ImageViewExample.ImageViewExample for activity   
ImageViewExample.ImageViewExample/.ImageViewExample: pid=418 uid=10050 gids={}
04-25 23:06:33.169: DEBUG/AndroidRuntime(418): Shutting down VM
04-25 23:06:33.169: WARN/dalvikvm(418): threadid=1: thread exiting with uncaught    
exception (group=0x4001d800)
04-25 23:06:33.229: ERROR/AndroidRuntime(418): FATAL EXCEPTION: main
04-25 23:06:33.229: ERROR/AndroidRuntime(418): java.lang.RuntimeException: Unable to 
start activity   
ComponentInfo{ImageViewExample.ImageViewExample/ImageViewExample.ImageViewExample
.ImageViewExample}: java.lang.NullPointerException
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at    
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
android.app.ActivityThread.access$2300(ActivityThread.java:125)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at    
android.os.Handler.dispatchMessage(Handler.java:99)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
android.os.Looper.loop(Looper.java:123)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at    
android.app.ActivityThread.main(ActivityThread.java:4627)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
java.lang.reflect.Method.invokeNative(Native Method)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
java.lang.reflect.Method.invoke(Method.java:521)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
dalvik.system.NativeStart.main(Native Method)
04-25 23:06:33.229: ERROR/AndroidRuntime(418): Caused by: 
java.lang.NullPointerException
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
ImageViewExample.ImageViewExample.MyImageView.<init>(MyImageView.java:32)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
ImageViewExample.ImageViewExample.ImageViewExample.onCreate(ImageViewExample.java:28)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at   
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     at 
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
04-25 23:06:33.229: ERROR/AndroidRuntime(418):     ... 11 more
04-25 23:06:33.279: WARN/ActivityManager(63):   Force finishing activity   
ImageViewExample.ImageViewExample/.ImageViewExample
04-25 23:06:33.839: WARN/ActivityManager(63): Activity pause timeout for 
HistoryRecord{4403fb30 ImageViewExample.ImageViewExample/.ImageViewExample}
04-25 23:06:45.281: WARN/ActivityManager(63): Activity destroy timeout for 
HistoryRecord{4403fb30 ImageViewExample.ImageViewExample/.ImageViewExample}
 04-25 23:10:06.659: DEBUG/SntpClient(63): request time failed: 
java.net.SocketException:   
 Address family not supported by protocol

Answer 1

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;

public class MyImageView extends View {

private static final int INVALID_POINTER_ID = -1;

    private Drawable mImage;
    private float mPosX;
    private float mPosY;

    private float mLastTouchX;
    private float mLastTouchY;
    private int mActivePointerId = INVALID_POINTER_ID;

    private ScaleGestureDetector mScaleDetector;
    private float mScaleFactor = 1.f;

    public MyImageView(Context context) {
        this(context, null, 0);
    mImage =  Drawable.createFromPath("/sdcard/filename");

        mImage.setBounds(0, 0, width, height);
    }

    public MyImageView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        // Let the ScaleGestureDetector inspect all events.
        mScaleDetector.onTouchEvent(ev);

        final int action = ev.getAction();
        switch (action & MotionEvent.ACTION_MASK) {
        case MotionEvent.ACTION_DOWN: {
            final float x = ev.getX();
            final float y = ev.getY();

            mLastTouchX = x;
            mLastTouchY = y;
            mActivePointerId = ev.getPointerId(0);
            break;
        }

        case MotionEvent.ACTION_MOVE: {
            final int pointerIndex = ev.findPointerIndex(mActivePointerId);
            final float x = ev.getX(pointerIndex);
            final float y = ev.getY(pointerIndex);

            // Only move if the ScaleGestureDetector isn't processing a gesture.
            if (!mScaleDetector.isInProgress()) {
                final float dx = x - mLastTouchX;
                final float dy = y - mLastTouchY;

                mPosX += dx;
                mPosY += dy;

                invalidate();
            }

            mLastTouchX = x;
            mLastTouchY = y;

            break;
        }

        case MotionEvent.ACTION_UP: {
            mActivePointerId = INVALID_POINTER_ID;
            break;
        }

        case MotionEvent.ACTION_CANCEL: {
            mActivePointerId = INVALID_POINTER_ID;
            break;
        }

        case MotionEvent.ACTION_POINTER_UP: {
            final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) 
                    >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
            final int pointerId = ev.getPointerId(pointerIndex);
            if (pointerId == mActivePointerId) {
                // This was our active pointer going up. Choose a new
                // active pointer and adjust accordingly.
                final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
                mLastTouchX = ev.getX(newPointerIndex);
                mLastTouchY = ev.getY(newPointerIndex);
                mActivePointerId = ev.getPointerId(newPointerIndex);
            }
            break;
        }
        }

        return true;
    }

    @Override
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        canvas.save();
        Log.d("DEBUG", "X: "+mPosX+" Y: "+mPosY);
        canvas.translate(mPosX, mPosY);
        canvas.scale(mScaleFactor, mScaleFactor);
        mImage.draw(canvas);
        canvas.restore();
    }

    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            mScaleFactor *= detector.getScaleFactor();

            // Don't let the object get too small or too large.
            mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 10.0f));

            invalidate();
            return true;
        }
    }

}

要在您的活动中调用它， setContentView(new MyImageView(this));