android - 检查 Intent.ACTION_VIEW 上的用户操作

Question

我有一个包含一些文件的 ListView ，可以有各种类型，如 pdf 或文档。当用户单击一个文件时，我会得到文件 mime 类型并启动一个 Intent ，让用户选择使用哪个应用程序打开它file.What 我想知道的是用户选择了一些东西，或者简单地按下并没有选择任何东西。直到现在我尝试的是做一个 startActivityForResult 并检查是否成功，但它总是返回 RESULT_CANCELED

    static final int SELECTED_VIEWER = 1;

    Intent intent = new Intent(Intent.ACTION_VIEW);     
    intent.setDataAndType(Uri.parse(filePath), mimetype);
    try {
        startActivityForResult(intent, SELECTED_VIEWER);
    }catch (ActivityNotFoundException e) {
        Toast.makeText(getActivity(), 
           Strings.ERROR_NO_VIEWER, 
            Toast.LENGTH_SHORT).show();
    }

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
     if (requestCode == SELECTED_VIEWER) {
         if (resultCode == Activity.RESULT_CANCELED ) {
             //do something
         }
     }
 }

我什至尝试了 startActivityForResult(Intent.createChooser 但仍然无济于事。我怎么知道用户是否选择了该列表中的某些内容，或者他是否取消了打开？

Answer 1

在 Android Developer 中写于 Activities

In other protocols (such as ACTION_MAIN or ACTION_VIEW), you may not get the result when you expect.

你不能指望 Action View 返回你所期望的，所以我所做的是实现一个自定义警报对话框，显示所有可以打开某个文件的可能应用程序，一个稍微修改过的版本，如图所示 Custom intent chooser

那些想知道的代码，它采用文件路径作为参数，并通过获取 mimetype 向您显示可以处理该文件类型的所有已安装应用程序。使用完整路径工作。可以用

AlertDialogIntentChooser alertDialog = new  AlertDialogIntentChooser(filePath,getActivity());
alertDialog.show();

这是一个类，它也可以接受一个可选的委托(delegate)来进行 Activity 回调

public class AlertDialogIntentChooser {
private String filePath;
private Activity activity;
private AlertDialog dialog;
private AlertDialogDelegate delegate;
private ListItem[] items;

public AlertDialogIntentChooser(String filePath,Activity activity){
    this.filePath = filePath;
    this.activity = activity;
    init();
}

public void setDialogDelegate(AlertDialogDelegate delegate){
    this.delegate = delegate;
}

private void init(){

    initApplicationItems();

    AlertDialog.Builder builder = new AlertDialog.Builder(activity);
    builder.setTitle(Strings.STRING_SELECT_APPLICATION);
    builder.setIcon(R.drawable.ic_share);

    builder.setOnCancelListener(new OnCancelListener() {

        @Override
        public void onCancel(DialogInterface paramDialogInterface) {
            if(delegate!=null)
                delegate.onDialogCancelled(paramDialogInterface);
        }
    });

    builder.setAdapter(adapter, new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {         

            Intent intentPdf = new Intent(Intent.ACTION_VIEW);
            MimeTypeMap myMime = MimeTypeMap.getSingleton();
            String fileExt = MimeTypeMap.getFileExtensionFromUrl(Uri.parse(filePath));
            String mimeType = myMime.getMimeTypeFromExtension(fileExt);                 
            intentPdf.setClassName(items[which].context, items[which].packageClassName);
            intentPdf.setDataAndType(Uri.parse(filePath), mimeType);
            try {
                activity.startActivity(intentPdf);
                dialog.dismiss();
                if(delegate!=null)
                    delegate.onItemSelected(items[which].context, items[which].packageClassName);
            }catch (ActivityNotFoundException e) {
                Toast.makeText(activity, 
                        Strings.ERROR_NO_VIEWER, 
                        Toast.LENGTH_SHORT).show();
                dialog.dismiss();
            }               
        }
    });

    dialog = builder.create();        
}

private void initApplicationItems(){
    Intent intentPdf = new Intent(Intent.ACTION_VIEW);

    MimeTypeMap myMime = MimeTypeMap.getSingleton();
    String fileExt = MimeTypeMap.getFileExtensionFromUrl(Uri.parse(filePath));
    String mimeType = myMime.getMimeTypeFromExtension(fileExt);             
    intentPdf.setDataAndType(Uri.parse(filePath), mimeType);
    PackageManager pm = activity.getPackageManager();
    List<ResolveInfo> resInfos = pm.queryIntentActivities(intentPdf, 0);

    items = new ListItem[resInfos.size()];
    int i = 0;
    for (ResolveInfo resInfo : resInfos) {
        String context = resInfo.activityInfo.packageName;
        String packageClassName = resInfo.activityInfo.name;
        CharSequence label = resInfo.loadLabel(pm);
        Drawable icon = resInfo.loadIcon(pm);
        items[i] = new ListItem(label.toString(), icon, context, packageClassName);
        ++i;
    }
}

public void show(){
    dialog.show();
}

private ListAdapter adapter = new ArrayAdapter<ListItem>(
          activity,
    android.R.layout.select_dialog_item,
    android.R.id.text1,
    items){

    public View getView(int position, View convertView, ViewGroup parent) {

        View v = super.getView(position, convertView, parent);
        TextView tv = (TextView)v.findViewById(android.R.id.text1);

        int dpS = (int) (72 * activity.getResources().getDisplayMetrics().density *  0.5f);
        items[position].icon.setBounds(0, 0, dpS, dpS);
        tv.setCompoundDrawables(items[position].icon, null, null, null);

        int dp5 = (int) (5 * activity.getResources().getDisplayMetrics().density *  0.5f);
        tv.setCompoundDrawablePadding(dp5);

        return v;
    }
};

class ListItem {
     public final String name;
     public final Drawable icon;
     public final String context;
     public final String packageClassName;

     public ListItem(String text, Drawable icon, String context, String packageClassName) {
         this.name = text;
         this.icon = icon;
         this.context = context;
         this.packageClassName = packageClassName;
     }

     @Override
     public String toString() {
         return name;
     }
 }

 public static interface AlertDialogDelegate{
     public void onDialogCancelled(DialogInterface paramDialogInterface);
     public void onItemSelected(String packageName, String className);
 }
}