java如何正确使用加载数组和保存数组方法?
我有下面的代码,它是为用户单击按钮而设计的,当他们单击按钮时,他们正在查看的特定字符串将被优先显示并存储在其他地方
我有两个问题
我现在的东西怎么了?当你点击按钮时它崩溃了
对于要加载并保存到数组中的字符串,如何完成加载数组方法,以便用户以后可以看到该数组
谢谢你的时间
fav.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
loadArray("favorites");
favorites = Arrays.copyOf(favorites, favorites.length+1);
favorites[favorites.length]=display.getText().toString();
saveArray(favorites, "favorites");
}
});
home.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent openStartingPoint = new Intent("starting.rt.Menu2");
startActivity(openStartingPoint);
}
});
search.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent openStartingPoint = new Intent("starting.rt.Search");
startActivity(openStartingPoint);
}
});
moreapps.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent goToMarket;
goToMarket = new Intent(Intent.ACTION_VIEW, Uri
.parse("market://search?q=pub:\"Wompa\""));
startActivity(goToMarket);
}
});
}
public String[] loadArray(String arrayName) {
SharedPreferences prefs = getSharedPreferences("preferencename", 0);
int size = prefs.getInt(arrayName + "_size", 0);
String array[] = new String[size];
for(int i=0;i<size;i++)
array[i] = prefs.getString(arrayName + "_" + i, null);
return array;
}
public boolean saveArray(String[] array, String arrayName) {
SharedPreferences prefs = getSharedPreferences("preferencename", 0);
SharedPreferences.Editor editor = prefs.edit();
editor.putInt(arrayName +"_size", array.length);
for(int i=0;i<array.length;i++)
editor.putString(arrayName + "_" + i, array[i]);
return editor.commit();
}
原木猫
05-08 23:10:51.329: I/Process(495): Sending signal. PID: 495 SIG: 9
05-08 23:11:02.360: D/dalvikvm(504): GC_EXTERNAL_ALLOC freed 44K, 53% free 2553K/5379K, external 1625K/2137K, paused 221ms
05-08 23:11:08.599: D/dalvikvm(504): GC_EXTERNAL_ALLOC freed 16K, 51% free 2644K/5379K, external 2707K/3308K, paused 174ms
05-08 23:11:12.570: D/AndroidRuntime(504): Shutting down VM
05-08 23:11:12.570: W/dalvikvm(504): threadid=1: thread exiting with uncaught exception (group=0x40015560)
05-08 23:11:12.599: E/AndroidRuntime(504): FATAL EXCEPTION: main
05-08 23:11:12.599: E/AndroidRuntime(504): java.lang.NullPointerException
05-08 23:11:12.599: E/AndroidRuntime(504): at starting.rt.Base$1.onClick(Base.java:52)
05-08 23:11:12.599: E/AndroidRuntime(504): at 安卓.view.View.performClick(View.java:2485)
05-08 23:11:12.599: E/AndroidRuntime(504): at 安卓.view.View$PerformClick.run(View.java:9080)
05-08 23:11:12.599: E/AndroidRuntime(504): at 安卓.os.Handler.handleCallback(Handler.java:587)
05-08 23:11:12.599: E/AndroidRuntime(504): at 安卓.os.Handler.dispatchMessage(Handler.java:92)
05-08 23:11:12.599: E/AndroidRuntime(504): at 安卓.os.Looper.loop(Looper.java:123)
05-08 23:11:12.599: E/AndroidRuntime(504): at 安卓.app.ActivityThread.main(ActivityThread.java:3683)
05-08 23:11:12.599: E/AndroidRuntime(504): at java.lang.reflect.Method.invokeNative(Native Method)
05-08 23:11:12.599: E/AndroidRuntime(504): at java.lang.reflect.Method.invoke(Method.java:507)
05-08 23:11:12.599: E/AndroidRuntime(504): at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
05-08 23:11:12.599: E/AndroidRuntime(504): at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:597)
05-08 23:11:12.599: E/AndroidRuntime(504): at dalvik.system.NativeStart.main(Native Method)
05-08 23:11:17.869: I/Process(504): Sending signal. PID: 504 SIG: 9
# 1 楼答案
loadArray
函数返回String[]
。您可能希望像这样使用它:如您在第二部分中所要求的,可以稍后使用此数组。希望这有帮助
更新[根据您的评论]
因此,如果您想在TextView中获取文本并将其添加到列表/字符串数组中:
1)尝试从TextView获取字符串
2)使用“loadArray”从SharedReferences获取现有列表:
3)向其中添加新字符串:
4)再次保存它