加载网络图片显示大图

怼烎@ 2022-08-20 14:21 230阅读 0赞

1.将图片的uri列表和下标传给ImagePagerActivity

public void imageBrower(int position, ArrayList<String> urls2) {
        Intent intent = new Intent(this, ImagePagerActivity.class);
        intent.putExtra(ImagePagerActivity.EXTRA_IMAGE_URLS, urls2);
        intent.putExtra(ImagePagerActivity.EXTRA_IMAGE_INDEX, position);
        this.startActivity(intent);
    }

2.给ImagePagerActivity布局：layout里布局：

<?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">
    
        <com.yangzi.homeimprovement.imagedemo.HackyViewPager
            android:id="@+id/pager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@android:color/black"/>
    
        <TextView
            android:id="@+id/indicator"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom"
            android:background="@android:color/transparent"
            android:gravity="center"
            android:text="@string/viewpager_indicator"
            android:textColor="@android:color/white"
            android:textSize="18sp"/>
         </FrameLayout>

3.关联布局--->写一个继承FragmentStatePagerAdapter的类显示图片

--->更新下标

/** * 图片查看器 */ public class ImagePagerActivity extends FragmentActivity {
        private static final String STATE_POSITION = "STATE_POSITION";
        public static final String EXTRA_IMAGE_INDEX = "image_index";
        public static final String EXTRA_IMAGE_URLS = "image_urls";
    
        private ViewPager mPager;
        private int pagerPosition;
        private TextView indicator;
    
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.image_detail_pager);
    
            pagerPosition = getIntent().getIntExtra(EXTRA_IMAGE_INDEX, 0);
            ArrayList<String> urls = getIntent().getStringArrayListExtra(EXTRA_IMAGE_URLS);//intent传过来的显示大图的Uri
    
            mPager = (ViewPager) findViewById(R.id.pager);
            ImagePagerAdapter mAdapter = new ImagePagerAdapter(getSupportFragmentManager(), urls);
            mPager.setAdapter(mAdapter);
            indicator = (TextView) findViewById(R.id.indicator);
    
            CharSequence text = getString(R.string.viewpager_indicator, 1, mPager.getAdapter().getCount());
            indicator.setText(text);
            // 更新图片的下标
            mPager.setOnPageChangeListener(new OnPageChangeListener() {
    
                @Override
                public void onPageScrollStateChanged(int arg0) {
                }
    
                @Override
                public void onPageScrolled(int arg0, float arg1, int arg2) {
                }
    
                @Override
                public void onPageSelected(int arg0) {
                    CharSequence text = getString(R.string.viewpager_indicator, arg0 + 1, mPager.getAdapter().getCount());// 后面的参数填充参数1
    
                    indicator.setText(text);
                }
    
            });
            if (savedInstanceState != null) {
                pagerPosition = savedInstanceState.getInt(STATE_POSITION);
            }
            mPager.setCurrentItem(pagerPosition);
        }
    
        @Override
        public void onSaveInstanceState(Bundle outState) {
            outState.putInt(STATE_POSITION, mPager.getCurrentItem());
        }
        
        // 显示图片
        private class ImagePagerAdapter extends FragmentStatePagerAdapter {
      //当 Fragment 对应的数据集发生改变时,用它较好
    
            public ArrayList<String> fileList;
    
            public ImagePagerAdapter(FragmentManager fm, ArrayList<String> fileList) {
                super(fm);
                this.fileList = fileList;
            }
    
            @Override
            public int getCount() {
                return fileList == null ? 0 : fileList.size();//如果uri列表不为空，得到uriList的大小
            }
    
            @Override
            public Fragment getItem(int position) {
                String url = fileList.get(position);
                return ImageDetailFragment.newInstance(url);
            }
        }
    }

4.显示图片 这里用到了使用[Android-Universal-Image-Loader 图片异步加载类库][Android-Universal-Image-Loader]，

/** * 单张图片显示Fragment */ public class ImageDetailFragment extends Fragment {
        private String mImageUrl;
        private ImageView mImageView;
        private ProgressBar progressBar;
        private PhotoViewAttacher mAttacher;
    
        public static ImageDetailFragment newInstance(String imageUrl) {
            final ImageDetailFragment f = new ImageDetailFragment();
    
            final Bundle args = new Bundle();
            args.putString("url", imageUrl);
            f.setArguments(args);//Fragment不要用构造方法传参
            return f;
        }
    
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            //在构造方法里用setArguments传递过来的参数不为空，就得到大图的Url
            mImageUrl = getArguments() != null ? getArguments().getString("url") : null;
        }
    
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            final View v = inflater.inflate(R.layout.image_detail_fragment, container, false);
            mImageView = (ImageView) v.findViewById(R.id.image);
            mAttacher = new PhotoViewAttacher(mImageView);
    
            mAttacher.setOnPhotoTapListener(new PhotoViewAttacher.OnPhotoTapListener() {
    
                @Override
                public void onPhotoTap(View arg0, float arg1, float arg2) {
                    getActivity().finish();
                }
            });
    
            progressBar = (ProgressBar) v.findViewById(R.id.loading);
            return v;
        }
    
        @Override
        public void onActivityCreated(Bundle savedInstanceState) {
            super.onActivityCreated(savedInstanceState);
    
            ImageLoader.getInstance().displayImage(mImageUrl, mImageView, new SimpleImageLoadingListener() {
                @Override
                public void onLoadingStarted(String imageUri, View view) {
                    progressBar.setVisibility(View.VISIBLE);
                }
    
                @Override
                public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
                    String message = null;
                    switch (failReason.getType()) {
                        case IO_ERROR:
                            message = "下载错误";
                            break;
                        case DECODING_ERROR:
                            message = "图片无法显示";
                            break;
                        case NETWORK_DENIED:
                            message = "网络有问题，无法下载";
                            break;
                        case OUT_OF_MEMORY:
                            message = "图片太大无法显示";
                            break;
                        case UNKNOWN:
                            message = "未知的错误";
                            break;
                    }
                    Toast.makeText(getActivity(), message, Toast.LENGTH_SHORT).show();
                    progressBar.setVisibility(View.GONE);
                }
    
                @Override
                public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
                    progressBar.setVisibility(View.GONE);
                    mAttacher.update();
                }
            });
        }
    }

[Android-Universal-Image-Loader]: http://blog.csdn.net/vipzjyno1/article/details/23206387