Question

我正在尝试使用Authorites.class中的intent传递String数据到Issues.class。选择单选按钮并单击按钮时，第一个活动必须显示吐司，并将单选按钮值传递给下一个活动。当我选择单选按钮并按下Authorites.class中的按钮时，应用程序将停止并退出。 Plz找到我哪里出错了

 public class Authorities extends AppCompatActivity {

 /**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
//private GoogleApiClient client;
 RadioButton auth_button;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_authorities);
    final RadioGroup auth_grp = (RadioGroup) findViewById(R.id.rgrp);
    Button button1 = (Button) findViewById(R.id.authselect);

    button1.setOnClickListener( new View.OnClickListener(){

    @Override
    public void onClick (View v){
        // store the text corresponding to  the RadioButton which is clicke
        int sa = auth_grp.getCheckedRadioButtonId();
        auth_button = (RadioButton) findViewById(sa);
    //           String auth=auth_button.getText().toString();
         Toast.makeText(Authorities.this, auth_button.getText(), Toast.LENGTH_SHORT).show();
        Intent i;
        i=new Intent(Authorities.this, Issues.class);
   //            Intent i = new       Intent().setClassName("com.example.chethan.wapp.Authorities", "com.example.chethan.wapp.Issues");
  //            i.putExtra("Auth",auth);
  // Starts TargetActivity
  //            Authorities.this.startActivity(i);
        startActivity(i);
    }
    });
 }

Issues.class应该接收从先前活动返回的Intent数据

 public class Issues extends AppCompatActivity {
CheckBox mws,sl,swc,sws,dr;
Button b2;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
  //  mws=(CheckBox)findViewById(R.id.mws);
 //   sl=(CheckBox)findViewById(R.id.sl);
  //  swc=(CheckBox)findViewById(R.id.swc);
 //   sws=(CheckBox)findViewById(R.id.sws);
 //   dr=(CheckBox)findViewById(R.id.dr);

    b2=(Button)findViewById(R.id.nxt);
  Bundle extras = getIntent().getExtras();
    String value1 = extras.getString("Auth");

   Toast.makeText(getApplicationContext(),"Authority you chose is:\n"+value1,Toast.LENGTH_LONG).show();

}

这是日志猫：

02-29 10：54：00.594 1960-1960 / com.example.chethan.wapp E / AndroidRuntime：FATAL EXCEPTION：main 过程：com.example.chethan.wapp，PID：1960 java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.chethan.wapp / com.example.chethan.wapp.Issues}：java.lang.NullPointerException 在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2184）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2233）在android.app.ActivityThread.access $ 800（ActivityThread.java:135）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1196）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:136）在android.app.ActivityThread.main（ActivityThread.java:5001） at java.lang.reflect.Method.invokeNative（Native Method）在java.lang.reflect.Method.invoke（Method.java:515）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:785）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:601） at dalvik.system.NativeStart.main（Native Method）引起：java.lang.NullPointerException 在com.example.chethan.wapp.Issues.onCreate（Issues.java:34）在android.app.Activity.performCreate（Activity.java:5231）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1087）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2148）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2233）在android.app.ActivityThread.access $ 800（ActivityThread.java:135）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1196）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:136）在android.app.ActivityThread.main（ActivityThread.java:5001） at java.lang.reflect.Method.invokeNative（Native Method）在java.lang.reflect.Method.invoke（Method.java:515）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:785）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:601）在dalvik.system.NativeStart.main（本地方法）

Answer 1

因为你从问题类的Intent的getString（＆＃34; Auth＆＃34;）中获取字符串value1数据，但是在Authorities类中你没有在Intent obj中输入任何（＆＃34; Auth＆＃34;）值。所以取消注释这条线......

           i.putExtra("Auth",auth);

然后运行项目......

不幸的是，App已停止 - 在两个活动之间传递意图数据

1 个答案: