问题
I have a table of 40 squares and each has an ID. When I'm passing Bundle from another activity I need to extract Note, Color and ID from that bundle. And then the app will change/add text and change background of the square specified by extracted ID. Each square has ID of int format. Each ID passed from other activity is in string format. I can't figure out how to make it to findViewById(R.id.passed_id), and how to get two different formats working together. I've tried to change ID of each square but eclipse says that ID have to have a letter along with a number. I'm lost....Here's the code:
package com.tt;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.content.res.Resources;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity
{
String gotNotes;
String n;
String gotDOW;
String gotID;
public String Id;
String gotHour;
TextView notes;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initialize();
Button settings = (Button)findViewById(R.id.settings);
Bundle gotPackage = getIntent().getExtras();
if (gotPackage != null){
gotNotes = gotPackage.getString("AddedNote");
// if (gotNotes.equals(" ")){n = "Empty";}else n = gotNotes;
//gotDOW = gotPackage.getString("Day");
//gotHour = gotPackage.getInt("Hour");
gotID = gotPackage.getString("ID");
Id = gotID;
notes.setText(gotNotes + (" \n") + gotID);
}
else{}
settings.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Intent i = new Intent(v.getContext(),Settings.class);
startActivityForResult(i,0);
}
});
}
private void initialize()
{
// TODO Auto-generated method stub
notes = (TextView)findViewById(R.id.);
notes.setGravity(Gravity.CENTER);
notes.setTextSize(TypedValue.COMPLEX_UNIT_SP, 12);
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
UPDATE
Ok.. here's the log:
12-27 16:18:55.661: D/AndroidRuntime(12497): Shutting down VM
12-27 16:18:55.661: W/dalvikvm(12497): threadid=1: thread exiting with uncaught exception (group=0x40abf228)
12-27 16:18:55.671: E/AndroidRuntime(12497): FATAL EXCEPTION: main
12-27 16:18:55.671: E/AndroidRuntime(12497): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tt/com.tt.MainActivity}: java.lang.NullPointerException
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2194)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2229)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.app.ActivityThread.access$600(ActivityThread.java:139)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1261)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.os.Handler.dispatchMessage(Handler.java:99)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.os.Looper.loop(Looper.java:154)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.app.ActivityThread.main(ActivityThread.java:4944)
12-27 16:18:55.671: E/AndroidRuntime(12497): at java.lang.reflect.Method.invokeNative(Native Method)
12-27 16:18:55.671: E/AndroidRuntime(12497): at java.lang.reflect.Method.invoke(Method.java:511)
12-27 16:18:55.671: E/AndroidRuntime(12497): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
12-27 16:18:55.671: E/AndroidRuntime(12497): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
12-27 16:18:55.671: E/AndroidRuntime(12497): at dalvik.system.NativeStart.main(Native Method)
12-27 16:18:55.671: E/AndroidRuntime(12497): Caused by: java.lang.NullPointerException
12-27 16:18:55.671: E/AndroidRuntime(12497): at com.tt.MainActivity.initialize(MainActivity.java:69)
12-27 16:18:55.671: E/AndroidRuntime(12497): at com.tt.MainActivity.onCreate(MainActivity.java:30)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.app.Activity.performCreate(Activity.java:4531)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071)
12-27 16:18:55.671: E/AndroidRuntime(12497): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2150)
12-27 16:18:55.671: E/AndroidRuntime(12497): ... 11 more
回答1:
You can get an identifier from a string by using:
notes = (TextView)findViewById(getResources().getIdentifier(VIEW_NAME, "id", getPackageName()));
Where VIEW_NAME is whatever identifier string you're generating. After that, you can set the text of it like you currently are. This also works if you need to get strings and drawables as well, just change id to the appropriate type.
回答2:
Assuming you're passing in the actual string "R.id.passed_id", I would recommend passing in the integer value instead. Thus, simply pass in R.id.passed_id.
All values in the R file of an application are simply integers that are mapped to resource locations. The findById() methods are only looking for integers, so if you start the Activity and pass in the integer value of the resource you want, it will find it.
Note: This will only work if the resources are within the same application. R files remain constant for an application, but they can change from one app to another even if they have the same name. If, however, the two activities fall under the same application package, it will work.
回答3:
Man I'm not understating what exactly you want to do. Id is the id off an android widget then on function initialize() you should cast string to int this way: Integer.ValueOf(Id) Hope this is what you want.
来源：https://stackoverflow.com/questions/14056817/findviewbyid-where-id-is-dynamic-string