android - AccessibilityService 中的粘贴在 API22 中有效，在 API17 中无效

Question

当我在 API22 上运行我的代码时，它工作得很好，将“测试测试”粘贴到启动 AccessibilityEvent 的应用程序中我所需的 EditText 中。但是当我在 API 17 上运行它时，它不起作用。它将数据复制到剪辑，但无法粘贴。我需要该机制在 API 16 及更高版本上工作。

这是我目前的代码:

public class MyAccessibilityService extends AccessibilityService {
    @Override
    public void onAccessibilityEvent(AccessibilityEvent event) {
        AccessibilityNodeInfo nodeInf = null;
        AccessibilityNodeInfo nodeInfo = null;
        final int eventType = event.getEventType();
        String eventText = null;
        switch(eventType) {
            case AccessibilityEvent.TYPE_VIEW_CLICKED:
                eventText = "Clicked: ";
                nodeInf = this.getRootInActiveWindow();
                Log.d("AccessibilityNodeInfo", ""+ nodeInf.getChildCount());
                nodeInf.recycle();
                break;
            case AccessibilityEvent.TYPE_VIEW_FOCUSED:
                AccessibilityRecordCompat record = AccessibilityEventCompat.asRecord(event);
                AccessibilityNodeInfoCompat source = record.getSource();

                ClipboardManager clipboard = (ClipboardManager) this.getSystemService(Context.CLIPBOARD_SERVICE);
                ClipData clip = ClipData.newPlainText("label", "TESTING TESTING");
                clipboard.setPrimaryClip(clip);

                source.performAction(AccessibilityNodeInfoCompat.ACTION_PASTE);
                //}

                Log.d("AccessibilityNodeInfo", ""+ source.getClassName());
                Intent intent = new Intent(MyAccessibilityService.this, TestActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                intent.addFlags(Intent.FLAG_ACTIVITY_MULTIPLE_TASK);
                startActivity(intent);
                break;
        }


        eventText = eventText + event.getText();

        // Do something nifty with this text, like speak the composed string
        // back to the user.
        Log.d("Information", eventText);
        Toast.makeText(getApplicationContext(), eventText + " " + android.os.Build.VERSION.SDK_INT,
                Toast.LENGTH_LONG).show();
    }
}

Answer 1

不幸的是AccessibilityNodeInfo.ACTION_PASTE在 API 级别 18 中添加，因此它不适用于 API 17 及更低版本。 AccessibilityNodeInfoCompat 只是现有功能的包装，它不提供缺失功能的自定义实现。

v4 支持库的来源非常清楚:

当您在 AccessibilityNodeInfoCompat 中调用 performAction 时，支持库调用 IMPL.performAction [1]

public boolean performAction(int action) {
    return IMPL.performAction(mInfo, action);
}

当 API 级别为 16 和 17 时，

IMPL 为 AccessibilityNodeInfoJellybeanImpl [2]

if (Build.VERSION.SDK_INT >= 22) {
    IMPL = new AccessibilityNodeInfoApi22Impl();
} else if (Build.VERSION.SDK_INT >= 21) {
    IMPL = new AccessibilityNodeInfoApi21Impl();
} else if (Build.VERSION.SDK_INT >= 19) { // KitKat
    IMPL = new AccessibilityNodeInfoKitKatImpl();
} else if (Build.VERSION.SDK_INT >= 18) { // JellyBean MR2
    IMPL = new AccessibilityNodeInfoJellybeanMr2Impl();
} else if (Build.VERSION.SDK_INT >= 16) { // JellyBean
    IMPL = new AccessibilityNodeInfoJellybeanImpl();
} else if (Build.VERSION.SDK_INT >= 14) { // ICS
    IMPL = new AccessibilityNodeInfoIcsImpl();
} else {
    IMPL = new AccessibilityNodeInfoStubImpl();
}

这是 AccessibilityNodeInfoJellybeanImpl 中的 performAction [3]

public static boolean performAction(Object info, int action, Bundle arguments) {
    return ((AccessibilityNodeInfo) info).performAction(action, arguments);
}

可以看到标准android.view.accessibility.AccessibilityNodeInfo的支持库调用performAction，所以如果系统不支持ACTION_PASTE v4 支持库也不支持 ACTION_PASTE。

您可以检查此代码是否支持 ACTION_PASTE:

AccessibilityNodeInfoCompat source = record.getSource();
int supportedActions = source.getActions();
boolean isSupported = (supportedActions & AccessibilityNodeInfoCompat.ACTION_PASTE) == AccessibilityNodeInfoCompat.ACTION_PASTE;
Log.d(TAG, String.format("AccessibilityNodeInfoCompat.ACTION_PASTE %1$s supported", isSupported ? "is" : "is NOT"));