How can I detect which layout is selected by Andro

问题:

Assume I have an activity with three different layouts in different resource folders. For example:

layout-land/my_act.xml
layout-xlarge/my_act.xml
layout-xlarge-land/my_act.xml

In different devices and different positions one of them is selected by Android.
How can I find out which one is selected programmatically?

Does Android have any API that returns these layouts to the program?

---

Edit: Graham Borland's solution has a problem in some situations that I mentioned in the comments.

回答1:

You could create a values-<config> directory for each of your supported configurations. Inside of each of those directories, create a strings.xml with a single selected_configuration string which describes the current configuration. At runtime, fetch the string using the standard getString method, which will do the configuration resolution for you and return the correct string for the configuration. This is untested.

回答2:

You can set a different android:tag attribute on the views in each different resource file, and read the tag back at runtime with View.getTag().

Example:

layout-xlarge-land/my_act.xml

<View
    android:id="@+id/mainview"
    android:tag="xlarge-landscape"
/>

layout-xlarge/my_act.xml

<View
    android:id="@+id/mainview"
    android:tag="xlarge-portrait"
/>

MyActivity.java

String tag = view.getTag();
if (tag.equals("xlarge-landscape") {
    ...
}

回答3:

You can try to repeat this algorithm "How Android Finds the Best-matching Resource" - it's quite simple, especially if you have different layouts only for different screens.

回答4:

My answer is implemented from @Graham Borland

 @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        DisplayMetrics metrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metrics);
        switch(metrics.densityDpi){
             case DisplayMetrics.DENSITY_LOW:

             if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE)
             {
               Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
               String tag = view.getTag();
               if (tag.equals("small-landscape") {
                .....
              }
             } 
            else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) 
            {
            Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
             String tag = view.getTag();
               if (tag.equals("small-potrait") {
                .....
              }
            }
            break;

             case DisplayMetrics.DENSITY_MEDIUM:

             if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE)
             {
               Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
               String tag = view.getTag();
               if (tag.equals("medium-landscape") {
                .....
              }
             } 
            else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) 
            {
            Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
             String tag = view.getTag();
               if (tag.equals("medium-potrait") {
                .....
              }
            }
             break;

             case DisplayMetrics.DENSITY_HIGH:

               if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE)
             {
               Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
               String tag = view.getTag();
               if (tag.equals("large-landscape") {
                .....
              }
             } 
            else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) 
            {
            Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
             String tag = view.getTag();
               if (tag.equals("large-potrait") {
                .....
              }
            }
             break;
        }

This will work in API lavel 4 or higher.

回答5:

I am assuming you are using setContentView(int resID) to set the content of your activities.

---

METHOD 1 (This is my answer)

Now in all your layouts make sure that the root view always has the right tag:

example:

layout-xlarge/main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:tag="xlarge-landscape"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

</LinearLayout>

layout-small/main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:tag="small"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

</LinearLayout>

Now let your activities extend this activity:

package shush.android.screendetection;

import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class SkeletonActivity extends Activity {

    protected String resourceType;

    @Override
    public void setContentView(int layoutResID) {
        LayoutInflater inflater = getLayoutInflater();
        View view = inflater.inflate(layoutResID, null);
        resourceType = (String)view.getTag();
        super.setContentView(view);
    }
}

In this case, you can use the resourceType to know what is the resource identifier used.

---

METHOD 2 (This was my answer but before posting I thought of the better one)

Now in all your layouts make sure that the root view always has the right tag:

example:

layout-xlarge/main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:tag="xlarge-landscape"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

</LinearLayout>

layout-small/main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:tag="small"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

</LinearLayout>

Now let your activities extend this activity:

package shush.android.screendetection;

import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class SkeletonActivity extends Activity {

    @Override
    public void setContentView(int layoutResID) {
        LayoutInflater inflater = getLayoutInflater();
        View view = inflater.inflate(layoutResID, null);
        fix(view, view.getTag());
        super.setContentView(view);
    }

    private void fix(View child, Object tag) {
        if (child == null)
            return;

        if (child instanceof ViewGroup) {
            fix((ViewGroup) child, tag);
        }
        else if (child != null) {
            child.setTag(tag);
        }
    }

    private void fix(ViewGroup parent, Object tag) {
        for (int i = 0; i < parent.getChildCount(); i++) {
            View child = parent.getChildAt(i);
            if (child instanceof ViewGroup) {
                fix((ViewGroup) child, tag);
            } else {
                fix(child, tag);
            }
        }
    }
}

In this case all your views in your hierarchy will have the same tag.

回答6:

I dont know the exact way to find it. But we can find it in different way.

Add one textview in all the layouts.(visibility hidden). Assign values like xlarge, land, xlarge-land accordingly.

In program, get the value from textview. Somehow we can get to know like this.

回答7:

You can get info about screen orientation and size from Resources object. From there you can understand which layout is used.

getResources().getConfiguration().orientation; - returns either Configuration.ORIENTATION_PORTRAIT or Configuration.ORIENTATION_LANDSCAPE.

int size = getResources().getConfiguration().screenLayout; - returns mask of screen size. You can test against Small, Normal, Large, xLarge sizes. For example:

if ((size & Configuration.SCREENLAYOUT_SIZE_XLARGE)==Configuration.SCREENLAYOUT_SIZE_XLARGE)

回答8:

Your question is as same as this How to get layout xml file path?
You can add a Hidden Text View with corresponding Folder names in the xml Get the String in the text view by

TextView path = (TextView)findViewbyid(R.id.hiddentextview); 
 String s =  path.gettext().tostring();

Make sure that all the id's of the text view are same.

Example

if your xml is in `normal-mdpi` in hidden textview hard code `normal-mdpi`
if your xml is in `large-mdpi` in hidden textview hard code `large-mdpi`