The project needs to realize the function of picture viewing. Using ImageView can't scale, using the system's picture viewer can't meet their own customized needs, so I used Viewpager + PhotoView to realize it.

Introducing PhotoView

Github link for PhotoView , PhotoView is designed to help developers easily scale Android ImageView.

1. Configure warehouse address

Add the following code to the build.gradle file of the project

allprojects {
    repositories {
        jcenter()
        maven { url "https://jitpack.io" }
    }
}

If there are multiple URLs, you can write

allprojects {
    repositories {
        jcenter()
        maven { url 'https://esri.bintray.com/arcgis' }
        maven { url "https://jitpack.io" }
    }
}

2. Import third party Library

Add in the build.gradle file of your project's app module

compile 'com.github.chrisbanes:PhotoView:2.1.3'

3. Control use

After introducing the tripartite library, you can use the PhotoView control

<com.github.chrisbanes.photoview.PhotoView
    android:id="@+id/photo_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

The realization of picture viewer

1. Define TaskBigImgActivity.java for viewing pictures

public class TaskBigImgActivity extends BaseActivity {

    @BindView(R.id.header_title)
    TextView headerTitle;
    @BindView(R.id.header_left_img)
    ImageView headerLeftImg;
    @BindView(R.id.big_img_vp)
    ViewPager bigImgVp;
    @BindView(R.id.header_right_tv)
    TextView headerRightTv;
    private int position;
    private ArrayList<String> paths;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_task_big_img);
        ButterKnife.bind(this);
        Intent intent = getIntent();
        position = intent.getIntExtra("position", 0);
        paths = intent.getStringArrayListExtra("paths");
        String title = intent.getStringExtra("title");
        headerTitle.setText(title);
        headerLeftImg.setVisibility(View.VISIBLE);
        headerRightTv.setVisibility(View.VISIBLE);
        headerRightTv.setText(position + 1 + "/" + paths.size());
        initView();
    }

    private void initView() {
        bigImgVp.setAdapter(new PagerAdapter() {
            @Override
            public int getCount() {
                return paths == null ? 0 : paths.size();
            }

            @Override
            public boolean isViewFromObject(View view, Object o) {
                return view == o;
            }

            @Override
            public Object instantiateItem(ViewGroup container, int position) {
                View adView = LayoutInflater.from(TaskBigImgActivity.this).inflate(R.layout.item_big_img, null);
                PhotoView icon = (PhotoView) adView.findViewById(R.id.flaw_img);
                icon.setBackgroundColor(getResources().getColor(R.color.colorBlack));
                Glide.with(TaskBigImgActivity.this)
                        .load(paths.get(position))
                        .into(icon);
                container.addView(adView);
                return adView;
            }

            @Override
            public void destroyItem(ViewGroup container, int position, Object object) {
                container.removeView((View) object);
            }
        });

        bigImgVp.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                headerRightTv.setText(position + 1 + "/" + paths.size());
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }

        });

        bigImgVp.setCurrentItem(position, true);
    }

    @OnClick(R.id.header_left_img)
    public void onClick() {
        finish();
    }
}

Corresponding layout file activity task big img.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
    tools:context="com.cnbs.cableinspection.user.activity.TaskBigImgActivity">

    <include layout="@layout/header" />

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

</LinearLayout>

Layout item > big > img.xml used in Adapter

<?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="wrap_content"
    android:background="@color/colorWhite"
    android:gravity="center">

    <com.github.chrisbanes.photoview.PhotoView
        android:id="@+id/flaw_img"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

2. Call to view pictures

private ArrayList<String> recordPaths = new ArrayList<>(); //Picture collection of defect record
...
Intent imgIntent = new Intent(TaskRecordActivity.this, TaskBigImgActivity.class);
imgIntent.putStringArrayListExtra("paths",recordPaths);
imgIntent.putExtra("title","Defect record picture");
imgIntent.putExtra("position",msg.arg2);
startActivity(imgIntent);

position refers to the pictures viewed

Here you can view the picture freely, and realize the transformation of scale, rotation and so on.