Android实现图片点击放大
笑忘书客 人气:0在我的项目中，有点击图片banner后放大浏览的功能。我的做法就是创建一个专门的图片显示Activity，布局里面用ViewPage,这样就能控制图片的左右滑动，并且控制首先显示第几张图片。
功能是ok的，显示也是正常的。但我花费了好几天的时间来实现、完善这个功能。
ShowMoreImageActivity
/**
* 图片放大
*/
public class ShowMoreImageActivity extends BaseActivity {
@FindId(R.id.vp)
private ViewPager vp;
@FindId(R.id.ll_point)
private LinearLayout ll_point;
private List<String> imgs;
@FindId(R.id.btn_save)
private ImageView btn_save;
private int index;
public static int type;
private Activity activity;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_more_image);
initViews();
activity = this;
}
private void initViews() {
AutoFindId.findId(context);
imgs = (ArrayList<String>) getIntent().getSerializableExtra("img");
index = getIntent().getIntExtra("index", 0);
type = getIntent().getIntExtra("type", 0);
vp.setAdapter(new MoreImgPagerAdapter(context, imgs));
vp.addOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageSelected(int arg0) {
index = arg0;
setUpPoint(imgs.size(), arg0);
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
});
setUpPoint(imgs.size(), 0);
vp.setCurrentItem(index);
}
protected void downLoad(final String urls) {
String[] split = urls.split("\\?");
final String url = split[0];
if (url.startsWith("file")) {
G.toast(context, "此为本地图片，不用下载,路径为" + url.replace("file://", ""));
return;
}
if (OKHttpUtils.isNetworkAvailable(context)) {
G.showPd(context);
TDUtils.execute(new Runnable() {
@Override
public void run() {
try {
File file = new File(C.getDownloadPath());
if (!file.exists()) {
file.mkdir();
}
File jpg = new File(C.getDownloadPath() + G.urlToFileName(url));
// 如果已经存在则不需要下载
if (jpg != null && jpg.exists()) {
G.dismissProgressDialogInThread();
G.toastInThread(context,
"该文件已被下载到" + jpg.getParent() + context.getResources().getString(R.string.xia));
return;
}
// 先从缓存中查找
File tmpFile = NetAide.getBitmapUtils().getBitmapFileFromDiskCache(url);
if (tmpFile != null && tmpFile.exists()) {
G.look("---从缓存中查找到图片----");
Bitmap bm = BitmapFactory.decodeFile(tmpFile.getAbsolutePath());
FileOutputStream fos = new FileOutputStream(jpg);
bm.compress(CompressFormat.JPEG, 100, fos);
fos.close();
G.dismissProgressDialogInThread();
// 通知图库更新
C.noticeImageRefresh(context, jpg);
G.toastInThread(context, context.getResources().getString(R.string.downLoadUrl)
+ jpg.getParent() + context.getResources().getString(R.string.xia));
return;
}
// 从网络上下载保存
Bitmap bm = BitmapFactory.decodeStream(new URL(url).openStream());
FileOutputStream fos = new FileOutputStream(jpg);
bm.compress(CompressFormat.JPEG, 100, fos);
fos.close();
G.dismissProgressDialogInThread();
// 通知图库更新
C.noticeImageRefresh(context, jpg);
G.toastInThread(context, "你现在可以在图库中查看该图片了");
} catch (Exception e) {
e.printStackTrace();
G.dismissProgressDialogInThread();
G.toastInThread(context, context.getResources().getString(R.string.downLoadFail));
File jpg = new File(C.getDownloadPath() + G.urlToFileName(url));
if (jpg != null && jpg.exists()) {
jpg.delete();
}
}
}
});
}
}
private void setUpPoint(int size, int choose) {
ll_point.removeAllViews();
if (size <= 1) {
return;
}
for (int i = 0; i < size; i++) {
ImageView point = new ImageView(context);
point.setLayoutParams(new LinearLayout.LayoutParams(DensityUtil.dip2px(context, 15), -2));
point.setScaleType(ScaleType.FIT_CENTER);
if (i == choose) {
point.setImageResource(R.drawable.white_choosed);
} else {
point.setImageResource(R.drawable.white_no_choosed);
}
ll_point.addView(point);
}
}
public void doClcik(View view) {
switch (view.getId()){
case R.id.btn_save:
PermissionUtils permissionUtils = new PermissionUtils();
permissionUtils.setPermission(this, "存储", "保存图片", new PermissionUtils.AfterPermission() {
@Override
public void doNext() {
downLoad(imgs.get(index));
}
},Manifest.permission.WRITE_EXTERNAL_STORAGE);
break;
}
}
}
对应布局：
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/black"
android:orientation="vertical">
<androidx.viewpager.widget.ViewPager
android:id="@+id/vp"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginTop="25dp">
<LinearLayout
android:layout_width="50dp"
android:layout_height="match_parent"
android:onClick="onFinish">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginLeft="10dp"
android:background="@drawable/nav_back" />
</LinearLayout>
<View
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_weight="1" />
<ImageView
android:id="@+id/btn_save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginRight="10dp"
android:onClick="doClcik"
android:src="@drawable/download_img" />
</LinearLayout>
<LinearLayout
android:id="@+id/ll_point"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:layout_marginBottom="40dp"
android:gravity="center"
android:orientation="horizontal"/>
</FrameLayout>
MoreImgPagerAdapter
public class MoreImgPagerAdapter extends PagerAdapter {
private Context context;
private List<String> images;
private SparseArray<SoftReference<View>> ivs;
public MoreImgPagerAdapter(Context context, List<String> images) {
this.context = context;
this.images = images;
ivs = new SparseArray<SoftReference<View>>();
}
@Override
public int getCount() {
return images.size();
}
@Override
public void destroyItem(ViewGroup arg0, int arg1, Object arg2) {
SoftReference<View> reference = ivs.get(arg1);
if (reference != null && reference.get() != null) {
arg0.removeView(reference.get());
}
}
@Override
public Object instantiateItem(ViewGroup arg0, final int arg1) {
SoftReference<View> reference = ivs.get(arg1);
if (reference == null || reference.get() == null) {
View v = LayoutInflater.from(context).inflate(R.layout.item_show_more_image, null);
reference = new SoftReference<View>(v);
ivs.put(arg1, reference);
}
View v = reference.get();
final ViewHolder holder = new ViewHolder(v);
Glide.with(context).asBitmap().load(images.get(arg1)).into(holder.image);
arg0.addView(v);
return v;
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0.equals(arg1);
}
class ViewHolder {
@FindId(R.id.image)
private ImageView image;
@FindId(R.id.rl_percent)
private RelativeLayout rl_percent;
@FindId(R.id.tv_percent)
private TextView tv_percent;
@FindId(R.id.iv_top)
private ImageView iv_top;
public ViewHolder(View v) {
AutoFindId.findIdByView(this, v);
}
}
}
对应布局：
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@android:color/black" android:orientation="vertical" > <FrameLayout android:layout_width="match_parent" android:layout_height="match_parent" android:layout_marginBottom="50dp" android:layout_marginTop="70dp" > <ImageView android:layout_gravity="center" android:id="@+id/image" android:layout_width="match_parent" android:layout_height="match_parent" /> <ImageView android:id="@+id/iv_top" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="top|right" android:visibility="gone" android:background="@drawable/shuiyin" /> </FrameLayout> <RelativeLayout android:visibility="gone" android:id="@+id/rl_percent" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" > <ProgressBar android:layout_width="40dp" android:layout_height="40dp" /> <TextView android:id="@+id/tv_percent" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:textColor="@android:color/white" android:textSize="12sp" /> </RelativeLayout> </RelativeLayout>
上面都是次要的，因为我发现了一个更为简便的轮子。
在我的项目中，我只需要两步就完成了此功能。
第一步：
// 查看大图 implementation 'com.github.SherlockGougou:BigImageViewPager:v4_6.1.1'
第二步：
在点击图片事件那里调用：
ImagePreview .getInstance() // 上下文，必须是activity，不需要担心内存泄漏，本框架已经处理好； .setContext(context) // 设置从第几张开始看（索引从0开始） .setIndex(position) // 有三种设置数据集合的方式，根据自己的需求进行三选一： // 1：第一步生成的imageInfo List //.setImageInfoList(imageInfoList) // 2：直接传url List .setImageList(imageList) // 3：只有一张图片的情况，可以直接传入这张图片的url //.setImage(String image) // 开启预览 .start();
就这样完成了图片放大浏览、下载的功能，在这里记录下。
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