如何改变一个Android活动的背景颜色 [英] How to change background colour of an Android activity

问题描述

我想改变使用AlertDialog活动的背景色。这是我做了什么：

I want to change the background colour of an activity using AlertDialog. Here is what I have done:

private SharedPreferences prefs;    
private static final String SELECTED_ITEM = "SelectedItem"; 
private Editor sharedPrefEditor;

btnchangeColor = (ImageButton) findViewById(R.id.btnchangeColor);
btnchangeColor.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {

        final CharSequence[] items={"Red","Green","Blue", "Yellow", "#EE82EE"};

        AlertDialog.Builder builder = new AlertDialog.Builder(
                ContentView_2.this);

        builder.setTitle("Pick a Color");
        builder.setPositiveButton("ok", new DialogInterface.OnClickListener() { 

            @Override
            public void onClick(DialogInterface dialog, int which) {}
        });

        builder.setSingleChoiceItems(items, getSelectedItem(), new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                wvContent = (WebView) findViewById(R.id.wvContent);
                //LinearLayout ll=(LinearLayout)findViewById(R.id.wvContent); 

                if("Red".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.RED);
                }
                else if("Green".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.GREEN);
                    }
                else if("Blue".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.BLUE);
                    }
                else if("Yellow".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.YELLOW);
                    }
                else if("#EE82EE".equals(items[which]))
                {
                    wvContent.setBackgroundColor(Color.rgb(184,184,184));
                    }
                saveSelectedItem(which);
            }
        });
        builder.show();

    }});
    }

private int getSelectedItem() {
    if (prefs == null) {
        prefs = PreferenceManager
                .getDefaultSharedPreferences(this);
    }
    return prefs.getInt(SELECTED_ITEM, -1);
}

private void saveSelectedItem(int which) {
    if (prefs == null) {
        prefs = PreferenceManager
                .getDefaultSharedPreferences(this);
    }
    sharedPrefEditor = prefs.edit();
    sharedPrefEditor.putInt(SELECTED_ITEM, which);
    sharedPrefEditor.commit();
}

我还添加此code到的OnCreate ：

wvContent = (WebView) findViewById(R.id.wvContent); 
    wvContent.setBackgroundColor(getSelectedItem());

选择的颜色和Web视图（ wvContent ）的变化来选择颜色，但这不是保存和/或共享preferences加载。它返回到活动时重新启动其默认的颜色。

The colour is selected and the web view (wvContent) changes to chosen colour, BUT this is not saved to and/or loaded from Shared Preferences. It returns to its default colour when the activity is relaunched.

所以，问题是：如何才能正确地我保存选定的颜色来共享preferences并加载活动时重新登场

So the question is: How can properly I save the selected colour to SharedPreferences and load it when activity relaunches?

非常感谢您的帮助。

推荐答案

目前要保存在共享preferences选择的项目，而不是颜色code的位置。做到这一点的：

Currently you are saving position of selected item instead of color code in SharedPreferences. do it as:

wvContent = (WebView) findViewById(R.id.wvContent);
int bg_color=Color.TRANSPARENT;
 if("Red".equals(items[which]))
   {
       wvContent.setBackgroundColor(Color.RED);
       bg_color=Color.RED;
   }
 else if("Green".equals(items[which]))
  {
      wvContent.setBackgroundColor(Color.GREEN);
       bg_color=Color.GREEN;
  }
........
// save color in SharedPreferences
 saveSelectedItem(bg_color);

现在 getSelectedItem（）方法返回的颜色code为previously选择的值由微调。

Now getSelectedItem() method return color code for previously selected value from spinner.

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