我正在尝试编写代码，以便在设置中选中提示选项时，它应该显示提示，但是当我这样做时，它说没有定义getContext()方法。此方法将做什么，我必须在哪里定义它？
这是我的数学应用程序逻辑的代码：
package com.gamesup.braingame;
import java.util.Random;
import android.app.Activity;
import android.content.Intent;
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.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Easy extends Activity implements OnClickListener{
EditText display;
// This Array says , I am an array that holds arrays
String [][] multiArray = {{"4 + 5 = ", "9"},
{"20 * 3 - 1 = ","59"},
{"99 - 9 = ","90"},
{"50 / 2 + 18 = ","43"},
{"9 * 8 = ","72"},
{"4 + 20 - 20 = ","4"},
{"75 / 5 = ","15"},
{"99 - 1 * 3 = ","96"},
{"75 + 25 = ","100"}};
TextView displayExpression;
TextView displayAnswer;
TextView setAnswer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.easy);
display = (EditText)findViewById(R.id.displayText);
display.setText("?");
displayExpression = (TextView) findViewById(R.id.expression);
displayAnswer = (TextView) findViewById(R.id.answer_status);
setAnswer = (TextView) findViewById(R.id.answer);
Button generate = (Button) findViewById(R.id.random_gen);
generate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Random ranGenerate = new Random ();
int random = ranGenerate.nextInt(multiArray.length) ;
// Fetch your random question
String Rquestion = multiArray[random][0];
displayExpression.setText(Rquestion);
displayAnswer.setText("");
setAnswer.setText("?");
}
});
}
static boolean isEmpty = true;
public void num_Clicked(View v){
Button btn = (Button) findViewById(v.getId());
//getting the button object and using a view to get the id of the buttons
if (v.getId()== R.id.del_button){
String s = display.getText().toString();
s = s.substring(0, s.length() - 1);
display.setText(s);
return;
}
if(isEmpty){
display.setText(btn.getText());
isEmpty = false;
}
else{
display.append(btn.getText().toString());
}
}
//xml attribute to views called android:onclick, that can be used to handle
//clicks directly in the view's activity without need to implement any interface.
public void hash_Clicked(View v){
// Get the Answer from your EditText
String answer = display.getText().toString();
setAnswer.setText(answer);
// Using a for loop iterate on the base index
for(int i = 0; i < multiArray.length ; i++)
{
// if the answer is in position 1 of Array [i]
if(answer.equals(multiArray[i][1]))
{
// We have found the answer, Congratulate the User
displayAnswer.setTextColor(getResources().getColor(R.color.green));
displayAnswer.setText("CORRECT");
break;
}else{
// Tell them how bad they are since they can't solve simple equations!
displayAnswer.setTextColor(getResources().getColor(R.color.red));
displayAnswer.setText("INCORRECT");
//this is where i am getting the error
if(Prefs.getHints(getContext())){
}
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
super.onCreateOptionsMenu(menu);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.brain_game, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item){
switch (item.getItemId()){
case R.id.settings:
startActivity(new Intent(this,Prefs.class));
return true;
// more items go here if any
}
return false;
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
}
和 Prefs 类：
package com.gamesup.braingame;
import android.os.Bundle;
import android.preference.PreferenceActivity;
import android.preference.PreferenceManager;
import android.os.Bundle;
import android.content.Context;
public class Prefs extends PreferenceActivity {
//option names and default values
private static final String OPT_HINTS = "hints";
private static final boolean OPT_HINTS_DEF = true;
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
}
/**Get the current value of the hints option*/
public static boolean getHints (Context context){
return PreferenceManager.getDefaultSharedPreferences(context).getBoolean(OPT_HINTS, OPT_HINTS_DEF);
}
}
只需使用 this ，您已经在Activity中，这是一个Context：
if(Prefs.getHints(this)){
不需要使用其他上下文，因为如果您在 Activity 中调用该函数，那么您只需要传递 this 或 yourActivityName.this 这也是上下文。
所以改变
if(Prefs.getHints(this)){
或
if(Prefs.getHints(YourActivityName.this)){