Question

我正在开发我的第一个应用程序，它从/ data添加对local.prop的调整。我使用PreferenceActivity实现OnPreferenceChangeListener。我通过findPreference检测到密钥。

这是代码：

public boolean onPreferenceChange(Preference preference, Object newValue) {
    String key = preference.getKey();
    if ("first_key".equals(key) && !((CheckBoxPreference) preference).isChecked()) {
        // code
    }
    if ("second_key".equals(key) && !((CheckBoxPreference) preference).isChecked()) {
        // code
    }
}

因为我添加了第二个if（second_key）所以一切正常。错误是“无法访问的代码”。请帮我！我做错了什么？

Answer 1

您尚未添加所有代码。

这不会导致您写的错误。但是，如果您在第二个if之前返回，则可能会出现错误，然后将无法访问。

如果这是一个基于the docs的实现方法，您可能希望在结尾返回true，因此设置了首选项：

public boolean onPreferenceChange(Preference preference, Object newValue) {
    String key = preference.getKey();
    if ("first_key".equals(key) && !((CheckBoxPreference) preference).isChecked()) {
        // Do something if pref 1
    } else if ("second_key".equals(key) && !((CheckBoxPreference) preference).isChecked()) {
        // Do something if pref 2
    }
    return true;
}

请注意，您可以在此处使用else if，因为您不能同时使用这两个键。考虑到已经设置了侦听器，不同的首选项将对此方法进行不同的调用，考虑到您已设置它们。

Answer 2

package com.fast_gaming.performance;

import java.io.DataOutputStream;
import java.io.File;

import android.content.Context;
import android.os.Bundle;
import android.preference.CheckBoxPreference;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.Preference.OnPreferenceChangeListener;
import android.util.Log;
import android.widget.Toast;

public class Main extends PreferenceActivity implements OnPreferenceChangeListener {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.main);
        findPreference("enable").setOnPreferenceChangeListener(this);
        findPreference("debug.sf.nobootanimation").setOnPreferenceChangeListener(this);
    }
    public boolean onPreferenceChange(Preference preference, Object newValue) {
        String key = preference.getKey();
        if ("enable".equals(key) && !((CheckBoxPreference) preference).isChecked()) {
            try {
                Process enable = Runtime.getRuntime().exec("su");
                DataOutputStream outputStream = new DataOutputStream(enable.getOutputStream());
                outputStream.writeBytes("cd /data\n");
                outputStream.flush();
                outputStream.writeBytes("touch local.prop\n");
                outputStream.flush();
                outputStream.writeBytes("chmod 0777 local.prop\n");
                outputStream.flush();
                outputStream.writeBytes("exit\n");
                outputStream.flush();
                enable.waitFor();
                File file = new File("/system/bin/su");
                if (file.exists()) {
                    Log.d("Main", "This device is rooted!");
                    return true;
                } else {
                    Log.d("Main", "This device is not rooted!");
                    Context context = getApplicationContext();
                    CharSequence text = "This device is not rooted!";
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(context, text, duration);
                    toast.show();
                    return false;
                }
            } catch(Exception e) {
                return false;
            }
        } else {
            try {
                Process disable = Runtime.getRuntime().exec("su");
                DataOutputStream outputStream = new DataOutputStream(disable.getOutputStream());
                outputStream.writeBytes("cd /data\n");
                outputStream.flush();
                outputStream.writeBytes("rm local.prop\n");
                outputStream.flush();
                outputStream.writeBytes("exit\n");
                outputStream.flush();
                disable.waitFor();
                File file = new File("/system/bin/su");
                if (file.exists()) {
                    Log.d("Main", "This device is rooted!");
                    return true;
                } else {
                    Log.d("Main", "This device is not rooted!");
                    Context context = getApplicationContext();
                    CharSequence text = "This device is not rooted!";
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(context, text, duration);
                    toast.show();
                    return false;
                }
            } catch (Exception e) {
                return false;
            }
        }
        else if ("debug.sf.nobootanimation".equals(key) && !((CheckBoxPreference) preference).isChecked()) {
            try {
                Process enable1 = Runtime.getRuntime().exec("su");
                DataOutputStream outputStream = new DataOutputStream(enable1.getOutputStream());
                outputStream.writeBytes("cd /data\n");
                outputStream.flush();
                outputStream.writeBytes("echo \"debug.sf.nobootanimation=1\" > local.prop\n");
                outputStream.flush();
                outputStream.writeBytes("exit\n");
                outputStream.flush();
                enable1.waitFor();
                File file = new File("/system/bin/su");
                if (file.exists()) {
                    Log.d("Main", "This device is rooted!");
                    return true;
                } else {
                    Log.d("Main", "This device is not rooted!");
                    Context context = getApplicationContext();
                    CharSequence text = "This device is not rooted!";
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(context, text, duration);
                    toast.show();
                    return false;
                }
            } catch (Exception e) {
                return false;
            }
        } else {
            try {
                Process enable1 = Runtime.getRuntime().exec("su");
                DataOutputStream outputStream = new DataOutputStream(enable1.getOutputStream());
                outputStream.writeBytes("cd /data\n");
                outputStream.flush();
                outputStream.writeBytes("sed '/debug..sf.nobootanimation=1/d' filename.txt\n");
                outputStream.flush();
                outputStream.writeBytes("exit\n");
                outputStream.flush();
                enable1.waitFor();
                File file = new File("/system/bin/su");
                if (file.exists()) {
                    Log.d("Main", "This device is rooted!");
                    return true;
                } else {
                    Log.d("Main", "This device is not rooted!");
                    Context context = getApplicationContext();
                    CharSequence text = "This device is not rooted!";
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(context, text, duration);
                    toast.show();
                    return false;
                }
            } catch (Exception e) {
                return false;
            }
        } return true;
    }
}

这是完整的代码。我说了什么，什么都没发生。 Eclsipse对我说“令牌上的语法错误”，“删除此令牌”，如果我删除其他，再次“无法访问代码”......

OnPreferenceChangeListener无法访问的代码

2 个答案: