Using Intent in an Android application to show ano

问题:

In my Android application, I have two activity classes. I have a button on the first one and I want to show the second when it is clicked, but I get an error. Here are the classes:

public class FirstActivity extends Activity {

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    Button orderButton = (Button)findViewById(R.id.order);

    orderButton.setOnClickListener(new View.OnClickListener() {

      @Override
      public void onClick(View view) {
        Intent intent = new Intent(FirstActivity.this, OrderScreen.class);
        startActivity(intent);
      }

    });
  }
}

The second class that should show when the button is clicked, but never does:

public class OrderScreen extends Activity {

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.order);

    Button orderButton = (Button) findViewById(R.id.end);

    orderButton.setOnClickListener(new View.OnClickListener() {

      @Override
      public void onClick(View view) {
        finish();
      }

    });
  }
}

How do I create a button that will show the second activity?

回答1:

The issue was the OrderScreen Activity wasn\'t added to the AndroidManifest.xml. Once I added that as an application node, it worked properly.

<activity android:name=\".OrderScreen\" />

回答2:

Add this line to your AndroidManifest.xml:

<activity android:name=\".OrderScreen\" /> 

回答3:

----FirstActivity.java-----

    package com.mindscripts.eid;
    import android.app.Activity;
    import android.content.Intent;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;

public class FirstActivity extends Activity {

protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Button orderButton = (Button) findViewById(R.id.order);
    orderButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            Intent intent = new Intent(FirstActivity.this,OrderScreen.class);
            startActivity(intent);
        }
    });

 }
}

---

---OrderScreen.java---

    package com.mindscripts.eid;

    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;



    public class OrderScreen extends Activity {
@Override



protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second_class);
    Button orderButton = (Button) findViewById(R.id.end);
    orderButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            finish();
        }
    });

 }
}

---

---AndroidManifest.xml----

    <?xml version=\"1.0\" encoding=\"utf-8\"?>
    <manifest xmlns:android=\"http://schemas.android.com/apk/res/android\"
  package=\"com.mindscripts.eid\"
  android:versionCode=\"1\"
  android:versionName=\"1.0\">


<application android:icon=\"@drawable/icon\" android:label=\"@string/app_name\">
    <activity android:name=\".FirstActivity\"
              android:label=\"@string/app_name\">
        <intent-filter>
            <action android:name=\"android.intent.action.MAIN\" />
            <category android:name=\"android.intent.category.LAUNCHER\" />
        </intent-filter>
    </activity>
    <activity android:name=\".OrderScreen\"></activity>
</application>

回答4:

Use this code:

Intent intent=new Intent(context,SecondActivty.class);
startActivity(intent);
finish();

context: refer to current activity context,

please make sure that you have added activity in android manifest file.

Following code for adding activity in android manifest file

<Activity name=\".SecondActivity\">
</Activity>

回答5:

<activity android:name=\"[packagename optional].ActivityClassName\"></activity>

Simply adding the activity which we want to switch to should be placed in the manifest file

回答6:

When you create any activity in android file you have to specify it in AndroidManifest.xml like

<uses-sdk android:minSdkVersion=\"8\" />

<application
    android:icon=\"@drawable/ic_launcher\"
    android:label=\"@string/app_name\" >
    <activity
        android:name=\".MyCreativityActivity\"
        android:label=\"@string/app_name\" >
        <intent-filter>
            <action android:name=\"android.intent.action.MAIN\" />

            <category android:name=\"android.intent.category.LAUNCHER\" />
        </intent-filter>
    </activity>


     <activity android:name=\".OrderScreen\"></activity>


</application>

回答7:

b1 = (Button) findViewById(R.id.click_me);
        b1.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {

                Intent i = new Intent(MainActivity.this, SecondActivity.class);
                startActivity(i);

            }
        });

回答8:

add the activity in your manifest file

<activity android:name=\".OrderScreen\" />

回答9:

In the Manifest

<activity android:name=\".OrderScreen\" />

In the Java Code where you have to place intent code

startActivity(new Intent(CurrentActivity.this, OrderScreen.class);

回答10:

you can use the context of the view that did the calling. Example:

Button orderButton = (Button)findViewById(R.id.order);

orderButton.setOnClickListener(new View.OnClickListener() {

  @Override
  public void onClick(View view) {
    Intent intent = new Intent(/*FirstActivity.this*/ view.getContext(), OrderScreen.class);
    startActivity(intent);
  }

});

回答11:

Intent i = new Intent(\"com.Android.SubActivity\");
startActivity(i);