我制作了一个带有主要活动和偏好活动的小应用程序。这是 PrefsActivity:
public class PrefsActivity extends PreferenceActivity {
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.prefs);
}
}
然后我通过菜单从主活动触发 Preference 活动,如果选中复选框,则要求将音量设置为 0:
这是整个主要活动:
package com.stressedmanasoft.clickcounter;
import android.os.Bundle;
import android.app.Activity;
import android.view.*;
import android.widget.*;
import android.graphics.*;
import android.media.*;
import android.content.*;
import android.preference.*;
public class MainActivity extends Activity {
ImageView counter;
MediaPlayer clicksnd;
MediaPlayer resetsnd;
int x=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
counter = (ImageView) findViewById(R.id.Counter);
clicksnd = MediaPlayer.create(this, R.raw.clicksnd);
resetsnd = MediaPlayer.create(this, R.raw.resetsnd);
final TextView count = (TextView) findViewById(R.id.Count);
Typeface face = Typeface.createFromAsset(getAssets(), "Bohemian_typewriter.ttf");
count.setTypeface(face);
count.setText(""+x);
final Button countButton = (Button) findViewById(R.id.CountButton);
countButton.setOnClickListener (new View.OnClickListener() {
public void onClick(View v) {
clicksnd.start();
x = x+1;
count.setText(""+x);
}
});
final Button resetButton = (Button) findViewById(R.id.ResetButton);
resetButton.setOnClickListener (new View.OnClickListener() {
public void onClick(View v) {
resetsnd.start();
x = 0;
count.setText(""+x);
}
});
SharedPreferences myPreference = PreferenceManager.getDefaultSharedPreferences(this);
if(myPreference.getBoolean("checkBox", true)) {
clicksnd.setVolume(0, 0);}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
switch (item.getItemId())
{
case R.id.menu_settings:
Intent intent = new Intent(MainActivity.this, PrefsActivity.class);
startActivity(intent);
break;
}
return super.onOptionsItemSelected(item);
}
@Override
protected void onResume() {
super.onResume();
SharedPreferences myPreference = PreferenceManager.getDefaultSharedPreferences(this);
if(myPreference.getBoolean("checkBox", true)) {
clicksnd.setVolume(0, 0);
}
}
}
当我启动应用程序时,音频打开并且未选中复选框。如果我选中它,音频会按预期关闭,但如果我取消选中它,音频将保持关闭状态。为什么?
我应该添加一个监听器吗?
提前致谢