如何在投掷时更改imageview中的图像

Question

我有一个包含图像的relative layout。我在drawable 文件夹中有 10-20 张图片，还有一个 hashmap 用于存储这些图片。

在图像下方从左向右滑动时，它应该会更改为下一张图像。 在每次滑动时，它应该从hashmap 更改为下一张图片。

我对 java 和 android 编程完全陌生，感谢您以任何方式提供帮助。

这就是我所拥有的：

<?xml version="1.0" encoding="utf-8"?>
<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.bschiranth.homework2_chiranthbs.MainActivity">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/alice"
        android:onClick="onClick"
        android:clickable="true"
        android:src="@drawable/alice"/>

    <SeekBar
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/zoombar"
        android:max="100"
        android:progress="50"
       android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"/>
</RelativeLayout>

还有我的java：

@Override
public boolean onFling(MotionEvent event1, MotionEvent event2,
                       float velocityX, float velocityY) {
    Log.d("fling", "doing fling");

    MovieData movieData = new MovieData();
    HashMap hashMap = new HashMap();
    for(int i=1;i<movieData.getSize();i++)
    {
        hashMap = movieData.getItem(i);
    }

    if(event1.getX()-event2.getX()> SWIPE_MIN_DISTANCE && Math.abs(velocityX)>SWIPE_THRESHOLD_VELOCITY)
    {
        Toast.makeText(Activity_Control.this,
                "its flinging right to left", Toast.LENGTH_SHORT).show();
        imageView.setImageResource(R.drawable.avatar);
    }
    if(event2.getX()-event1.getX()> SWIPE_MIN_DISTANCE && Math.abs(velocityX)>SWIPE_THRESHOLD_VELOCITY)
    {
        Toast.makeText(Activity_Control.this,
                "its flinging left to right", Toast.LENGTH_SHORT).show();
        imageView.setImageResource(R.drawable.avengers);
    }
    return true;
}

Answer 1

你可以使用视图寻呼机而不是 imageview 更好

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:orientation="vertical" >

<android.support.v4.view.ViewPager
    android:id="@+id/myfivepanelpager"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

  </LinearLayout>

ViewPagerAdapter.java

        import android.app.Activity;
        import android.os.Parcelable;
       import android.support.v4.view.PagerAdapter;
      import android.support.v4.view.ViewPager;
     import android.view.View;
        import android.view.ViewGroup.LayoutParams;
     import android.widget.ImageView;
     import android.widget.ImageView.ScaleType;

      public class ViewPagerAdapter extends PagerAdapter {

      Activity activity;
      int imageArray[];

      public ViewPagerAdapter(Activity act, int[] imgArra) {
      imageArray = imgArra;
      activity = act;
       }

         public int getCount() {
         return imageArray.length;
         }

        public Object instantiateItem(View collection, int position) {
          ImageView view = new ImageView(activity);
         view.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
         LayoutParams.FILL_PARENT));
         view.setScaleType(ScaleType.FIT_XY);
         view.setBackgroundResource(imageArray[position]);
          ((ViewPager) collection).addView(view, 0);
          return view;
          }

          @Override
           public void destroyItem(View arg0, int arg1, Object arg2) {
          ((ViewPager) arg0).removeView((View) arg2);
           }

           @Override
            public boolean isViewFromObject(View arg0, Object arg1) {
            return arg0 == ((View) arg1);
           }

           @Override
         public Parcelable saveState() {
           return null;
           }
           }

PageIndicatorActivity.java

  public class PageIndicatorActivity extends Activity {

  @Override
  public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  ViewPagerAdapter adapter = new ViewPagerAdapter(this, imageArra);
  ViewPager myPager = (ViewPager) findViewById(R.id.myfivepanelpager);
  myPager.setAdapter(adapter);
  myPager.setCurrentItem(0);
  }

   private int imageArra[] = { R.drawable.antartica1, R.drawable.antartica2,
   R.drawable.antartica3, R.drawable.antartica4,
   R.drawable.antartica5, R.drawable.antartica6,
   R.drawable.antartica7, R.drawable.antartica8 };

   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
   getMenuInflater().inflate(R.menu.activity_main, menu);
   return true;
   }

    }

      public int getCount() {
      return imageArray.length;
        }

     public Object instantiateItem(View collection, int position) {
     ImageView view = new ImageView(activity);
     view.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
     LayoutParams.FILL_PARENT));
     view.setScaleType(ScaleType.FIT_XY);
     view.setBackgroundResource(imageArray[position]);
      ((ViewPager) collection).addView(view, 0);
       return view;
        }

      @Override
     public void destroyItem(View arg0, int arg1, Object arg2) {
    ((ViewPager) arg0).removeView((View) arg2);
    }

       @Override
      public boolean isViewFromObject(View arg0, Object arg1) {
       return arg0 == ((View) arg1);
      }

       @Override
     public Parcelable saveState() {
      return null;
     }
    }

Answer 2

这可以由ViewFlipper 完成，如下所述。

这是你的Activity.xml 文件

<ViewFlipper xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/view_flipper"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".HowToUseActivity" >
    <ImageView
        android:id="@+id/imageHowToUse"
        android:contentDescription="@string/app_name"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:src="@mipmap/screen_1" />
</ViewFlipper>

在您的活动类中声明所需的变量

private int number = 0;
private float initialX;
private ImageView imageView;

在您的Activity 的onCreate(...) 方法中检索ImageView

imageView = (ImageView) findViewById(R.id.imageHowToUse);

在同一活动中覆盖方法onTouchEvent(...)

@Override
public boolean onTouchEvent(MotionEvent event) {
    switch(event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            initialX = event.getX();
            break;
        case MotionEvent.ACTION_UP:
            float finalX = event.getX();
            if (initialX > finalX) {
                if (number >= 3) {
                    break;
                }
                next();
            } else {
                if(number <= 0) {
                    break;
                }
                previous();
            }
            break;
    }
    return false;
}

private void next() {
    number++;
    imageView.setImageResource(getImage());
}

private void previous() {
    number--;
    imageView.setImageResource(getImage());
}

然后编写方法getImage() 来获取下一张要显示的图像

private int getImage() {
    int resource = R.mipmap.screen_1;
    switch(number) {
        case 0:
            resource = R.mipmap.screen_1;
        break;
        case 1:
            resource = R.mipmap.screen_2;
            break;
        case 2:
            resource = R.mipmap.screen_3;
            break;
    }
    return resource;
}

这是我项目中的工作代码。它会帮助你。

注意：R.mipmap.screen_* 是我的资源目录中的图像资源。