Question

我已经使用ViewPager和毕加索制作了图像滑块。我在其下添加了XML for share按钮，并且在其中实现了onclick，但是在此之后我不知道该怎么做。

当我按下共享按钮时，我想共享图像。请帮我。我无法做到这一点。

在activity_main.xml中，我添加了名为page的viewpager和按钮。 Tts ID是share_image。

这是主要活动：

public class MainActivity extends AppCompatActivity {
    ViewPager viewPager;

    private int[] imageUrls = new int[]{
            R.raw.a,
            R.raw.b,
            R.raw.c //and many others
   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager = findViewById(R.id.view_pager);
        ViewPageAdapter adapter = new ViewPageAdapter(this, imageUrls);
        viewPager.setAdapter(adapter);
}
}

此viewPagerAdapter：

public class ViewPageAdapter extends PagerAdapter {

    private Context context;
    private int[] imageUrls;

    ViewPageAdapter(Context context, int[] imageUrls) {
        this.context = context;
        this.imageUrls = imageUrls;
    }

    @Override
    public int getCount() {
        return imageUrls.length;
    }

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

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        ImageView imageView = new ImageView(context);

        Picasso.get()
                .load(imageUrls[position])
                .into(imageView);
        container.addView(imageView);
        return imageView;
    }

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

Answer 1

您的ViewPager适配器：

public class ViewPageAdapter extends PagerAdapter {

    private Context context;
    private int[] imageUrls;
    public View currentImageView;

    ViewPageAdapter(Context context, int[] imageUrls) {
        this.context = context;
        this.imageUrls = imageUrls;
    }

    @Override
    public int getCount() {
        return imageUrls.length;
    }

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

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        ImageView view = new ImageView(context);

        Picasso.get()
                .load(imageUrls[position])
                .into(view);
        container.addView(view);
        return view;
    }

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

    @Override
    public void setPrimaryItem(ViewGroup container, int position, Object object) {
        currentImageView = (View)object;
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {
    ViewPager viewPager;
    ProgressBar progressBar;
    private int[] imageUrls = new int[]{
            R.drawable.after_cookie,
            R.drawable.before_cookie,
            R.drawable.androidparty
    };
//    private WebBackForwardList viewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        progressBar = findViewById(R.id.progress);
        viewPager = findViewById(R.id.view_pager);
        final ViewPageAdapter adapter = new ViewPageAdapter(this, imageUrls);
        viewPager.setAdapter(adapter);

        ImageView NextButton = findViewById(R.id.btnNext);
        NextButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                viewPager.setCurrentItem(getItem(+1), true); //getItem(+1) for next
            }
        });

        ImageView PreviousButton = findViewById(R.id.btnPrevious);
        PreviousButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                viewPager.setCurrentItem(getItem(-1), true);
            }
        });

        ImageView btnShare = findViewById(R.id.btnShare);
        btnShare.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (adapter.currentImageView == null) {
                    // Error: cannot get current image to share
                    return;
                }
                progressBar.setVisibility(View.VISIBLE);
                Bitmap bitmap = Bitmap.createBitmap(adapter.currentImageView.getWidth(), adapter.currentImageView.getHeight(), Bitmap.Config.ARGB_8888);
                adapter.currentImageView.draw(new Canvas(bitmap));
                Uri uri = saveImage(bitmap);
                shareImageUri(uri);
            }
        });
    }

    private void shareImageUri(Uri uri) {
        Intent intent = new Intent(android.content.Intent.ACTION_SEND);
        intent.putExtra(Intent.EXTRA_STREAM, uri);
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        intent.setType("image/png");
        startActivity(intent);
        progressBar.setVisibility(View.GONE);
    }

    private Uri saveImage(Bitmap image) {
        //TODO - Should be processed in another thread
        File imagesFolder = new File(getCacheDir(), "images");
        Uri uri = null;
        try {
            imagesFolder.mkdirs();
            File file = new File(imagesFolder, "shared_image.png");

            FileOutputStream stream = new FileOutputStream(file);
            image.compress(Bitmap.CompressFormat.PNG, 90, stream);
            stream.flush();
            stream.close();
            uri = FileProvider.getUriForFile(this, "com.example.recyclerview_codelabs.fileprovider", file);

        } catch (IOException e) {
            e.printStackTrace();
        }
        return uri;
    }

    private int getItem(int i) {
        return viewPager.getCurrentItem() + i;
    }
}

在您的 activity_main.xml

中

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ImageView
        android:id="@+id/main_image"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_gravity="center"
        tools:ignore="MissingConstraints" />

    <android.support.v4.view.ViewPager
        android:id="@+id/view_pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="8dp"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:context="com.example.recyclerview_codelabs.ZoomableImageView" />

    <ImageView
        android:id="@+id/btnShare"
        android:layout_width="0dp"
        android:adjustViewBounds="true"
        android:layout_height="wrap_content"
        android:layout_marginStart="10dp"
        android:layout_marginEnd="10dp"
        android:background="@drawable/circle_button"
        android:contentDescription="Share"
        android:foreground="?android:attr/selectableItemBackground"
        android:scaleType="centerCrop"
        android:src="@drawable/ic_share_black_24dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/btnPrevious"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintHorizontal_chainStyle="spread"
        app:layout_constraintStart_toStartOf="parent" />

    <ImageView
        android:id="@+id/btnPrevious"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="10dp"
        android:background="@drawable/circle_button"
        android:scaleType="fitCenter"
        android:adjustViewBounds="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/btnNext"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/btnShare"
        app:srcCompat="@android:drawable/ic_media_previous" />


    <ImageView
        android:id="@+id/btnNext"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:adjustViewBounds="true"
        android:layout_marginEnd="10dp"
        android:background="@drawable/circle_button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/btnDownload"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/btnPrevious"
        app:srcCompat="@android:drawable/ic_media_next" />

    <ImageView
        android:id="@+id/btnDownload"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="10dp"
        android:adjustViewBounds="true"
        android:background="@drawable/circle_button"
        android:scaleType="fitXY"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/btnNext"
        app:srcCompat="@android:drawable/stat_sys_download" />

    <ProgressBar
        android:id="@+id/progress"
        android:visibility="invisible"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_width="wrap_content"
        tools:visibility="visible"
        android:layout_height="wrap_content" />

</android.support.constraint.ConstraintLayout>

res> xml 文件夹中的

file_paths.xml ：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <paths xmlns:android="http://schemas.android.com/apk/res/android">
        <cache-path name="shared_images" path="images/"/>
    </paths>
</resources>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.recyclerview_codelabs">
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:allowBackup="false"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:ignore="GoogleAppIndexingWarning">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="com.example.recyclerview_codelabs.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths" />
        </provider>
    </application>
</manifest>

Answer 2

由于没有ViewPager幻灯片的代码，我将不得不假设您正在ImageView中显示图像。假设ImageView的ID为picture_view。

当您在幻灯片视图（片段或视图组）中引用它时，您将其引用为：

ImageView pictureView = findViewById(R.id.picture_view)

要共享它，您必须做两件事：

要共享图像，您必须将其保存在本地。

您将需要从imageView中获取位图。

Bitmap bmp = ((BitmapDrawable) pictureView.getDrawable()).getBitmap();

创建一个新文件。

然后，您需要将位图的压缩版本写入outputStream。

FileOutputStream out = new FileOutputStream(file);
            bmp.compress(Bitmap.CompressFormat.PNG, 90, out);
            out.close();

最后使用以下命令获取图像uri：

// NOTE: authority here should match authority in manifest declaration
Uri photoURI = FileProvider.getUriForFile(context,
                    "authority",
                    file);

为了以隐式意图使用保存的图像，您需要提供一个Uri。让我们使用photoURI。

intent.putExtra（Intent.EXTRA_STREAM，photoURI）;

让我知道您是否仍然无法解决问题，我会帮助您。

Answer 3

如果按钮设置正确，则可以在OnClick方法中添加此代码，

Intent sharingIntent = new Intent(android.content.Intent.ACTION_SEND);
sharingIntent.setType("image/*");
sharingIntent.putExtra(Intent.EXTRA_STREAM, imagePath);

startActivity(Intent.createChooser(sharingIntent, "Share Image via"));

创建共享意图设置共享类型，如何共享创建尚未共享的项目解析要共享给创建意图的主题解析要共享的邮件正文让用户有机会确定分享方式， //intent.createChooser

分享viewPager图片的意图

3 个答案: