Question

我正在关注Udemy.com的一些教程，我收到此语法错误“无法解析方法”isIntentAvailable（android.content.intent）' 我尝试在网上查找但无法找到解决方案。它被弃用了还是什么？

提前致谢

   mPerformButton = (Button) findViewById(R.id.performImplicit);
    mPerformButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            int position = mSpinner.getSelectedItemPosition();
            Intent implicitIntent = null;
            switch (position){

                case 0 :
                    //nothing selected
                    break;
                case 1:
                    //deltaprogram.us
                    implicitIntent = new Intent(Intent.ACTION_VIEW,
                            Uri.parse("http://deltaprogram.us"));
                    break;
                case 2:
                    //call someone
                    implicitIntent = new Intent(Intent.ACTION_DIAL,
                            Uri.parse("tel:(+000)8675309"));
                    break;
                case 3:
                    //map of YETspace
                    implicitIntent = new Intent(Intent.ACTION_VIEW,
                            Uri.parse("geo:30.2715,-97.742"));
                    break;
                case 4:
                    //take a picture( not returning it here though)
                    implicitIntent = new Intent("android.media.action.IMAGE_CAPTURE");
                    break;
                case 5:
                    //edit first contact
                    implicitIntent = new Intent(Intent.ACTION_EDIT,
                            Uri.parse("content://contacts/people/1"));
                    break;

            }

            if(implicitIntent != null){

                if(isIntentAvailable(implicitIntent) == true){ //Syntax Problem here
                    startActivity(implicitIntent);
                }else{
                    Toast.makeText(v.getContext(),"no application available", Toast.LENGTH_LONG).show();
                }
            }

        }
    });

Answer 1

添加此方法：

private boolean isIntentAvailable(Intent intent) {
    return getPackageManager().queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY).size() > 0;
}

Answer 2

添加功能定义：

/**
 * Indicates whether the specified action can be used as an intent. This
 * method queries the package manager for installed packages that can
 * respond to an intent with the specified action. If no suitable package is
 * found, this method returns false.
 *
 * @param context The application's environment.
 * @param action The Intent action to check for availability.
 *
 * @return True if an Intent with the specified action can be sent and
 *         responded to, false otherwise.
 */
public static boolean isIntentAvailable(Context context, String action) {
    final PackageManager packageManager = context.getPackageManager();
    final Intent intent = new Intent(action);
    List<ResolveInfo> list =
            packageManager.queryIntentActivities(intent,
                    PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}

Answer 3

使用标准库中的方法可能更好 - https://developer.android.com/reference/android/content/pm/PackageManager.html#resolveActivity(android.content.Intent,int)。它还具有 resolveService 和 resolveContentProvider 方法。

Answer 4

在[android blog]（https://android-developers.googleblog.com/2009/01/can-i-use-this-intent.html）中讨论了更多信息

/**
 * Indicates whether the specified action can be used as an intent. This
 * method queries the package manager for installed packages that can
 * respond to an intent with the specified action. If no suitable package is
 * found, this method returns false.
 *
 * @param context The application's environment.
 * @param action The Intent action to check for availability.
 *
 * @return True if an Intent with the specified action can be sent and
 *         responded to, false otherwise.
 */
public static boolean isIntentAvailable(Context context, String action) {
    final PackageManager packageManager = context.getPackageManager();
    final Intent intent = new Intent(action);
    List<ResolveInfo> list =
            packageManager.queryIntentActivities(intent,
                    PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}

并使用如下：

@Override
public boolean onPrepareOptionsMenu(Menu menu) {
    final boolean scanAvailable = isIntentAvailable(this,
        "com.google.zxing.client.android.SCAN");

    MenuItem item;
    item = menu.findItem(R.id.menu_item_add);
    item.setEnabled(scanAvailable);

    return super.onPrepareOptionsMenu(menu);
}

无法解析方法'isIntentAvailable（android.content.intent）'

4 个答案: