Question

我想让它可以点击ListView中的某个项目，然后打开一个活动来描述该用户点击的事情。我是Android开发的新手，所以很感激建设性的批评（Aka我知道这段代码很难看。）

package com.example.something.myapplication;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toast;

import static android.widget.AdapterView.*;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        String[]Planets = {"Mercury", "Venus", "Earth", "Mars" , "Jupiter", "Saturn", "Uranus", "Neptune", "Pluto"};

       ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,Planets)

        ListView PlanetList = (ListView) findViewById(R.id.PlanetList);

        PlanetList.setAdapter(adapter);

        PlanetList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override


            public void onItemClick(AdapterView<?> adapterView, View view, int position, long arg) {


                //What do I change to make the thing in the list open a new activity about that item on the list?


                String planetPicked = "You selected " + String.valueOf(adapterView.getItemAtPosition(position));

                                    Toast.makeText(MainActivity.this, planetPicked, Toast.LENGTH_SHORT).show();
                                }
                        });
                }


}

Answer 1

您需要一个意图：

Intent itemIntent = new Intent(MainActivity.this, your_seond_activity.class);
startActivity(itemIntent);

您可能希望将一些数据传递给新活动，为此您可以使用InentExtra，因此代码将为：

Intent itemIntent = new Intent(MainActivity.this, your_seond_activity.class);
itemIntent.putExtra("some_key", some_data);
startActivity(itemIntent);

在这里阅读：

http://developer.android.com/reference/android/content/Intent.html

在这里

Intent.html#putExtra

Answer 2

我首先要说的是，在java中，通常变量以小写字母开头，类以大写字母开头。

MainActivity.java文件的代码

getIntent().getStringExtra(getString("SOME_KEY_VALUE"));

在DesiredActivity.java文件中

访问您加载到意图使用方法

的附加内容

此示例用于获取您放入额外内容的字符串值。您可以在Android开发人员指南中找到其他意图和附加方法。

Answer 3

使用以下代码。供参考click here to see the full code

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

// Array of strings storing country names
String[] countries = new String[] {
    "India",
    "Pakistan",
    "Sri Lanka",
    "China",
    "Bangladesh",
    "Nepal",
    "Afghanistan",
    "North Korea",
    "South Korea",
    "Japan"
};

// Array of integers points to images stored in /res/drawable-ldpi/
int[] flags = new int[]{
    R.drawable.india,
    R.drawable.pakistan,
    R.drawable.srilanka,
    R.drawable.china,
    R.drawable.bangladesh,
    R.drawable.nepal,
    R.drawable.afghanistan,
    R.drawable.nkorea,
    R.drawable.skorea,
    R.drawable.japan
};

// Array of strings to store currencies
String[] currency = new String[]{
    "Indian Rupee",
    "Pakistani Rupee",
    "Sri Lankan Rupee",
    "Renminbi",
    "Bangladeshi Taka",
    "Nepalese Rupee",
    "Afghani",
    "North Korean Won",
    "South Korean Won",
    "Japanese Yen"
};

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // Each row in the list stores country name, currency and flag
    List<HashMap<String,String>> aList = new ArrayList<HashMap<String,String>>();

    for(int i=0;i<10;i++){
        HashMap<String, String> hm = new HashMap<String,String>();
        hm.put("txt", "Country : " + countries[i]);
        hm.put("cur","Currency : " + currency[i]);
        hm.put("flag", Integer.toString(flags[i]) );
        aList.add(hm);
    }

    // Keys used in Hashmap
    String[] from = { "flag","txt","cur" };

    // Ids of views in listview_layout
    int[] to = { R.id.flag,R.id.txt,R.id.cur};

    // Instantiating an adapter to store each items
    // R.layout.listview_layout defines the layout of each item
    SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), aList, R.layout.listview_layout, from, to);

    // Getting a reference to listview of main.xml layout file
    ListView listView = ( ListView ) findViewById(R.id.listview);

    // Setting the adapter to the listView
    listView.setAdapter(adapter);

    // Item Click Listener for the listview
    OnItemClickListener itemClickListener = new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View container, int position, long id) {
            // Getting the Container Layout of the ListView
            LinearLayout linearLayoutParent = (LinearLayout) container;

            // Getting the inner Linear Layout
            LinearLayout linearLayoutChild = (LinearLayout ) linearLayoutParent.getChildAt(1);

            // Getting the Country TextView
            TextView tvCountry = (TextView) linearLayoutChild.getChildAt(0);

            Toast.makeText(getBaseContext(), tvCountry.getText().toString(), Toast.LENGTH_SHORT).show();
        }
    };

    // Setting the item click listener for the listview
    listView.setOnItemClickListener(itemClickListener);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

}

如何点击ListView打开与该活动相关的新活动？

3 个答案:

MainActivity.java文件的代码

在DesiredActivity.java文件中