Question

在给大家惹麻烦之前，我做了很多尝试。我正在研究聊天应用程序，因为每个活动都有一个连接点。

Toast在Messege Activity上工作得非常好，因此发送Intent没有问题。但是当我尝试更新UI时，它会给我错误。

我发送这样的意图

intentt.putExtra("name", values[arg2]);

并获得如下的意图

Bundle extras = this.getIntent().getExtras();
String id = extras.getString("name");

我在TextView

中设置了ID的代码

else if (id != null) {

            // tx.setText(id);

            Thread thread = new Thread() {

                public void run() {

                    Handler handler = new Handler(Looper.getMainLooper());

                    handler.post(new Runnable() {

                        @Override
                        public void run() {
                            // TODO Auto-generated method stub
                            Toast.makeText(Messaging.this,
                                    "Something happened.", Toast.LENGTH_SHORT)
                                    .show();

                            tx.setText(id);
                        }
                    });

                };
            };
            thread.start();

        }

我在下面提到错误..

01-14 12:17:00.469: E/AndroidRuntime(5207): FATAL EXCEPTION: main
01-14 12:17:00.469: E/AndroidRuntime(5207): java.lang.NullPointerException
01-14 12:17:00.469: E/AndroidRuntime(5207):     at at.vcity.androidim.Messaging$2$1.run(Messaging.java:122)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at android.os.Handler.handleCallback(Handler.java:615)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at android.os.Looper.loop(Looper.java:137)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at android.app.ActivityThread.main(ActivityThread.java:4812)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at java.lang.reflect.Method.invokeNative(Native Method)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at java.lang.reflect.Method.invoke(Method.java:511)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
01-14 12:17:00.469: E/AndroidRuntime(5207):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

如果您正在进行活动，只需将代码更改为此代码。它会告诉你究竟是什么问题。

else if (id != null) {
                    // tx.setText(id);

                    Thread thread = new Thread() {

                        public void run() {

                        runOnUiThread(new Runnable() {

                    @Override
                    public void run() {


                                    // TODO Auto-generated method stub
                                    Toast.makeText(Messaging.this,
                                            "Something happened.", Toast.LENGTH_SHORT)
                                            .show();


                             if(tx!=null)
                             {
                                if(id!=null && id.length()>0)
                                {
                                   tx.setText(id);
                                  }
                                else
                                 {
                                Toast.makeText(Messaging.this,"id is null or is empty", Toast.LENGTH_SHORT).show();
                                 }
                             else
                             {
                              Toast.makeText(Messaging.this,"Tx is null", Toast.LENGTH_SHORT).show();
                              }

                                }
                }); 

                        };
                    };
                    thread.start();

                }

从另一个Activity发送意图时无法更改textview的文本

1 个答案: