Question

我有一个主要的活动，我打电话给

VersionSettings vs = new VersionSettings(this);
    if (vs.firstRun2()) 
        vs.versionCheckbox();

如果Android版本为1.6-2.1，我正在尝试将复选框（checkboxVideoType）设置为未选中状态

我只想在应用程序第一次运行时执行此操作，它永远不需要再次运行。

我认为当主要活动调用versionCheckbox（）时遇到问题，如果尝试运行内部代码将关闭复选框设置为false，则会强制关闭。

我对编程非常陌生，非常感谢对此有所帮助。我想我很接近，但需要推动。提前谢谢！

主要活动

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.widget.Button;
import android.widget.ImageView;



public class Nasatv extends Activity implements OnClickListener  {

boolean checkboxIsChecked;
SharedPreferences nasaTV_Prefs;




@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);

    setContentView(R.layout.main);

    getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.window_title);

    nasaTV_Prefs = getSharedPreferences("nasaTV_Prefs", 0);

    ChangeLog cl = new ChangeLog(this);
    if (cl.firstRun())
        cl.getLogDialog().show();

    VersionSettings vs = new VersionSettings(this);
    if (vs.firstRun2()) 
        vs.versionCheckbox();


    Button button = (Button) findViewById(R.id.button1);
    button.setOnClickListener(this); 


    Button button2 = (Button) findViewById(R.id.button2);
    button2.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            Intent i = new Intent(Nasatv.this, LaunchCalendar.class);
            startActivity(i);          

        }
    });


    Button button3 = (Button) findViewById(R.id.button3);
    button3.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            Intent i = new Intent(Nasatv.this, PhotoInfo.class);
            startActivity(i);   
        }
    }); 


    CheckConnectivity check = new CheckConnectivity();
    Boolean conn = check.checkNow(this.getApplicationContext());
    if(conn == true){
        ImageView updateImage = (ImageView) findViewById(R.id.updateImage);
        ImageDownloader downloader = new ImageDownloader(updateImage);
        downloader.execute("http://www.url.com/trl/ubox.jpg");
    } else {
        ImageView updateImage = (ImageView) findViewById(R.id.updateImage);
        updateImage.setImageResource(R.drawable.uboxerror);
    } 
}




public boolean onCreateOptionsMenu(Menu menu) 
{
    super.onCreateOptionsMenu(menu);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.options_menu, menu);
    return true;
}


public boolean onOptionsItemSelected(MenuItem item) 
{
    switch (item.getItemId()) 
    {
        case R.id.setting_title:
            Intent settingsActivity =new Intent(getBaseContext(), Settings.class);
            startActivity(settingsActivity);
            return true;

        case R.id.photo_archive:
            Intent archive = new Intent(Nasatv.this, PhotoArchive.class);
            startActivity(archive);
            return true;

        case R.id.n_web:
            Intent intent = new Intent(Intent.ACTION_VIEW,     Uri.parse("http://www.nasa.gov/"));
            startActivity(intent);
            return true;

        case R.id.exit_title:
            finish();
            return true;

        default:
            return super.onOptionsItemSelected(item);
    }
}



public void onResume() {
    super.onResume();
    checkboxIsChecked = nasaTV_Prefs.getBoolean("checkboxVideoType", true);
}



@Override
public void onClick(View v) {
    if (checkboxIsChecked) {
        Intent intent = new Intent(Intent.ACTION_VIEW,     Uri.parse("http://www.nasa.gov/multimedia/nasatv/nasatv_android_flash.html"));
         startActivity(intent);
    } else {
        Intent intent = new Intent(Intent.ACTION_VIEW,     Uri.parse("rtsp://nasadln.qt.llnwd.net/nasa101.sdp"));
        startActivity(intent);
    }

}


}

一次性跑步

 import android.content.Context;
 import android.content.SharedPreferences;
 import android.preference.PreferenceManager;
 import android.util.Log;
 import android.widget.CheckBox;



      public class VersionSettings {

    private final Context context;
    private String notRun, hasRun;
    private SharedPreferences run;
    private CheckBox checkboxVideoType;
    private SharedPreferences nasaTV_Prefs;
    private static final String HAS_RUN = "PREFS_HAS_RUN";


int currentapiVersion = android.os.Build.VERSION.SDK_INT;

/**
 * Constructor
 *
 * Retrieves whether the app has been run or not and saves to
 * SharedPreferences
 */
    public VersionSettings(Context context) {
    this.context = context;

    this.run = PreferenceManager.getDefaultSharedPreferences(context);

    // get run/not run string number, which is "1"
    this.notRun = run.getString(HAS_RUN, "");
    Log.d(TAG, "notRun: " + notRun);
    this.hasRun = context.getResources().getString(R.string.has_run_string);
    Log.d(TAG, "hasRun: " + hasRun);

    // save new number to preferences, which will be the same number, 
    // so this is run only the very first time the app is run
    SharedPreferences.Editor editor = run.edit();
    editor.putString(HAS_RUN, hasRun);
    editor.commit();
}


/**
 * @return  true if this version of your app is started for the first
 *          time
 */
public boolean firstRun2() {
    return  ! notRun.equals(hasRun);
} 


/**
 * @return  Change the checkboxVideoType to "unchecked" (false)
 *          
 */
public void versionCheckbox() {
//  this.context = context;

        if (currentapiVersion < android.os.Build.VERSION_CODES.FROYO){

            this.nasaTV_Prefs = PreferenceManager.getDefaultSharedPreferences(context);
            SharedPreferences.Editor editor = nasaTV_Prefs.edit();
            editor.putBoolean("checkboxVideoType", false);
            editor.commit();
        }
}

private static final String TAG = "VersionSettings";
}

偏好活动

import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;

public class Settings extends Activity implements OnCheckedChangeListener {

private CheckBox checkboxVideoType;
private SharedPreferences nasaTV_Prefs;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);

            setContentView(R.layout.preferences);

            getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.window_title);

            checkboxVideoType  =  (CheckBox) findViewById(R.id.checkboxVideoType);
            checkboxVideoType.setOnCheckedChangeListener(this);
            nasaTV_Prefs = getSharedPreferences("nasaTV_Prefs", 0);
            checkboxVideoType.setChecked(nasaTV_Prefs.getBoolean("checkboxVideoType", true));



            Button clbutton = (Button) findViewById(R.id.clbutton);
            clbutton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                ChangeLog cl = new ChangeLog(Settings.this);
                cl.getFullLogDialog().show();

        }
    });

    }

    public void onCheckedChanged(CompoundButton cb, boolean isChecked) {

          if (cb == checkboxVideoType){                     
            SharedPreferences.Editor editor = nasaTV_Prefs.edit();  
            editor.putBoolean("checkboxVideoType", isChecked);
            editor.commit();        // Commit the edit, i.e.,     save the state of the flag!
          }
    }

}

Answer 1

我刚注意到你的checkboxVideoType是这个类的私有属性，我在任何地方都看不到setter。如果它为null，您将得到一个NullPointerException，它将导致FC。您需要传递对复选框对象的引用（可能作为versionCheckbox()方法的参数）。

在android.os.Build.VERSION.SDK_INT和SharedPreferences方面需要帮助

1 个答案: