我有以下代码供用户单击按钮使用,当他们单击按钮时,正在查看的特定字符串将被收藏并存储在其他位置。
我有两个问题。
我现在所拥有的是什么问题?因为当您单击按钮时它会崩溃。
您将如何完成将要加载的字符串并将其保存到数组的load array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$1.onClick(Base.java:52) 05-08 23:11:12.599: E/AndroidRuntime(504): at android.view.View.performClick(View.java:2485) 05-08 23:11:12.599: E/AndroidRuntime(504): at android.view.View$PerformClick.run(View.java:9080) 05-08 23:11:12.599: E/AndroidRuntime(504): at android.os.Handler.handleCallback(Handler.java:587) 05-08 23:11:12.599: E/AndroidRuntime(504): at android.os.Handler.dispatchMessage(Handler.java:92) 05-08 23:11:12.599: E/AndroidRuntime(504): at android.os.Looper.loop(Looper.java:123) 05-08 23:11:12.599: E/AndroidRuntime(504): at android.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.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 05-08 23:11:12.599: E/AndroidRuntime(504): at com.android.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
loadArray函数返回String[]。您可能想要像这样使用它:
loadArray
String[]
String [] arr = loadArray("favorites");
该数组可以稍后在第二部分中使用。希望这可以帮助。
更新 [根据您的评论]
因此,如果您想在TextView中获取文本并希望将其添加到List / String数组中:
1)尝试从TextView获取字符串
TextView display = (TextView)findViewById(R.id.display); String toSave = display.getText().toString();
2)使用`loadArray’从SharedPreferences获取现有列表:
3)添加新的字符串:
ArrayList<String> arrList = new ArrayList<String>(); for (int i=0; i<arr.length(); i++) { arrList.add(arr[i]); //add old values to arraylist } // add new string to it: arrList.add(toSave); //Get back your array String [] array = arrList.toArray(new String[arrList.size()]);
4)再次保存。
saveArray(array, "favorites");