android gallery 自定义边框+幻灯片效果

2021-10-14 23:08:54

最近在项目中用到图片轮播，试了Gallery，ViewFlipper，ViewPager,感觉Gallery最符合需求，但是Gallery的系统边框很难看，项目中要求用自己的背景图片。

下面来看一下使用Gallery实现图片轮播

运行效果：

布局文件：

<FrameLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="10dp" >
<Gallery
android:id="@+id/gallery"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:fadingEdge="none"
android:spacing="0dp" />
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="18dp"
android:layout_gravity="bottom"
android:layout_marginBottom="3dp"
android:layout_marginLeft="3dp"
android:layout_marginRight="3dp"
android:background="#80776f63"
android:gravity="center" >
<ImageView
android:id="@+id/dot_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_dot_normal" />
<ImageView
android:id="@+id/dot_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_toRightOf="@+id/dot_1"
android:src="@drawable/ic_dot_normal" />
<ImageView
android:id="@+id/dot_3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_toRightOf="@+id/dot_2"
android:src="@drawable/ic_dot_normal" />
</RelativeLayout>
</FrameLayout>

其中， android:fadingEdge="none"消除图片两边的阴影。使用FrameLayout在底部显示小圆点

public class MainActivity extends Activity {
private Gallery mGallery;
private int index = 0;// 记录选中的图片位置
private ImageView[] mImageViewIds;// 小圆点ImageView数组
private static final int IMAGE_COUNT = 3;// 小圆点个数
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViews();
mImageViewIds[0].setImageDrawable(getBaseContext().getResources()
.getDrawable(R.drawable.ic_dot_focused));
ImageAdapteradapter = new ImageAdapter(this);
mGallery.setAdapter(adapter);
Timer timer = new Timer();
timer.schedule(task, 2000, 2000);
mGallery.setOnItemSelectedListener(onItemSelectedListener);
mGallery.setOnItemClickListener(onItemClickListener);
}
private void findViews() {
mGallery = (Gallery) findViewById(R.id.gallery);
mImageViewIds = new ImageView[] { (ImageView) findViewById(R.id.dot_1),
(ImageView) findViewById(R.id.dot_2),
(ImageView) findViewById(R.id.dot_3) };
}
private TimerTask task = new TimerTask() {
@Override
public void run() {
Message message = new Message();
message.what = 2;
index = mGallery.getSelectedItemPosition();
index++;
handler.sendMessage(message);
}
};
/**
* 开一个线程执行耗时操作
*/
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what) {
case 2:
mGallery.setSelection(index);
break;
default:
break;
}
}
};
/**
* 设置小圆点显示，position会一直增加，如果要循环显示图片，需要对position取余，否则数组越界
*/
private OnItemSelectedListener onItemSelectedListener = new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
int pos = position % IMAGE_COUNT;
mImageViewIds[pos].setImageDrawable(getBaseContext().getResources()
.getDrawable(R.drawable.ic_dot_focused));
if (pos > 0) {
mImageViewIds[pos - 1].setImageDrawable(getBaseContext()
.getResources().getDrawable(R.drawable.ic_dot_normal));
}
if (pos < (IMAGE_COUNT - 1)) {
mImageViewIds[pos + 1].setImageDrawable(getBaseContext()
.getResources().getDrawable(R.drawable.ic_dot_normal));
}
if (pos == 0) {
mImageViewIds[IMAGE_COUNT - 1]
.setImageDrawable(getBaseContext().getResources()
.getDrawable(R.drawable.ic_dot_normal));
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
};
/**
* 点击事件，点击图片进入SecondActivity
*/
private OnItemClickListener onItemClickListener = new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int pos,
long arg3) {
Intent intent = new Intent();
intent.setClass(MainActivity.this, SecondActivity.class);
startActivity(intent);
}
};
}

ImageAdapter类，重写android.widget.BaseAdapter，用于描述图像信息。

public class ImageAdapter extends BaseAdapter {
private Context context;
private int[] mImages = { R.drawable.bg_timeline_01,
R.drawable.bg_timeline_02, R.drawable.bg_timeline_03 };
private static final int IMAGE_PX_HEIGHT = 198;
public ImageAdapter(Context context) {
this.context = context;
}
@Override
public int getCount() {
return Integer.MAX_VALUE;//实现循环显示
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView = new ImageView(context);
imageView.setImageResource(mImages[position % mImages.length]);
imageView.setScaleType(ImageView.ScaleType.CENTER);
imageView.setLayoutParams(new Gallery.LayoutParams(
Gallery.LayoutParams.FILL_PARENT, IMAGE_PX_HEIGHT));
RelativeLayout borderImg = new RelativeLayout(context);
borderImg.setPadding(2, 2, 2, 2);
borderImg.setBackgroundResource(R.drawable.bg_gallery);//设置ImageView边框
borderImg.addView(imageView);
return borderImg;
}
}

如果用系统背景，可以这样写

int mGalleryItemBackground;
private Context mContext;
public ImageAdapter(Context context)
{
mContext = context;
// 获得Gallery组件的属性
TypedArray typedArray = obtainStyledAttributes(R.styleable.Gallery);
mGalleryItemBackground = typedArray.getResourceId(
R.styleable.Gallery_android_galleryItemBackground, 0);
}

在getview中设置

imageView.setBackgroundResource(mGalleryItemBackground);

Gallery组件属性信息定义在res\values\attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="Gallery">
<attr name="android:galleryItemBackground" />
</declare-styleable>
</resources>

详细讲解见http://www.eoeandroid.com/forum.php?mod=viewthread&tid=182297

自定义边框参考http://*.com/questions/4830173/change-border-style-in-gallery

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