Android ArrayAdapter<;按钮>;在ListView中显示按钮及其后面的对象引用
这是我第一个使用android的“项目”,我正在尝试制作一个活动应用程序,使用listview显示按钮列表。出于某种原因,my ArrayAdapter正确地显示了按钮,但在按钮后面,它显示了对象引用。所以当我用手机调试它时,我看到一个按钮和它后面的对象引用 我的活动如下所示:Android ArrayAdapter<;按钮>;在ListView中显示按钮及其后面的对象引用,android,listview,Android,Listview,这是我第一个使用android的“项目”,我正在尝试制作一个活动应用程序,使用listview显示按钮列表。出于某种原因,my ArrayAdapter正确地显示了按钮,但在按钮后面,它显示了对象引用。所以当我用手机调试它时,我看到一个按钮和它后面的对象引用 我的活动如下所示: package com.example.madelenko.showcase; import android.os.Bundle; import android.support.design.widget.Floati
package com.example.madelenko.showcase;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ArrayList<Button> projectList =
new ArrayList<Button>();
Button button1 = new Button(this);
Button button2 = new Button(this);
button1.setText("Spotify Streamer");
button2.setText("Scores App");
projectList.add(button1);
projectList.add(button2);
ArrayAdapter<Button> adapter =
new ArrayAdapter<Button>(this,R.layout.element_listview_layout,
R.id.list_item_string,projectList);
ListView listView = (ListView)findViewById(R.id.buttonListView);
listView.setAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/list_item_string"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:paddingLeft="8dp"
android:textSize="18sp"
android:textStyle="bold"
android:text=""/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/projectButton"
android:text="Hello world!"
android:layout_alignTop="@+id/list_item_string"
android:layout_centerHorizontal="true" />
</RelativeLayout>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.madelenko.showcase.MainActivityFragment"
tools:showIn="@layout/activity_main">
<ListView
android:layout_width="wrap_content"
android:layout_height="401dp"
android:id="@+id/buttonListView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_gravity="center" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="My nanodegree apps!"
android:id="@+id/textView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal|top" />
</FrameLayout>
public class ListViewDemo extends ListActivity {
private static final String[] items={"Spotify Streamer", "Scores App"};
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setListAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
items));
}
}
package com.example.madelenko.showcase;
导入android.os.Bundle;
导入android.support.design.widget.FloatingActionButton;
导入android.support.design.widget.Snackbar;
导入android.support.v7.app.AppActivity;
导入android.support.v7.widget.Toolbar;
导入android.view.view;
导入android.view.Menu;
导入android.view.MenuItem;
导入android.widget.ArrayAdapter;
导入android.widget.Button;
导入android.widget.ListView;
导入java.util.ArrayList;
公共类MainActivity扩展了AppCompatActivity{
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar Toolbar=(Toolbar)findViewById(R.id.Toolbar);
设置支持操作栏(工具栏);
ArrayList项目列表=
新的ArrayList();
Button button1=新按钮(此按钮);
Button button2=新按钮(此按钮);
按钮1.setText(“Spotify拖缆”);
按钮2.setText(“分数应用程序”);
项目列表。添加(按钮1);
项目列表。添加(按钮2);
阵列适配器=
新阵列适配器(此,R.layout.element_listview_布局,
R.id.list_item_string,projectList);
ListView ListView=(ListView)findViewById(R.id.buttonListView);
setAdapter(适配器);
}
@凌驾
公共布尔onCreateOptions菜单(菜单){
//为菜单充气;这会将项目添加到操作栏(如果存在)。
getMenuInflater().充气(右菜单菜单菜单主菜单);
返回true;
}
@凌驾
公共布尔值onOptionsItemSelected(菜单项项){
//处理操作栏项目单击此处。操作栏将
//自动处理Home/Up按钮上的点击,只要
//在AndroidManifest.xml中指定父活动时。
int id=item.getItemId();
//noinspection SimplifiableIf语句
if(id==R.id.action\u设置){
返回true;
}
返回super.onOptionsItemSelected(项目);
}
}
我的按钮元素布局如下所示:
package com.example.madelenko.showcase;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ArrayList<Button> projectList =
new ArrayList<Button>();
Button button1 = new Button(this);
Button button2 = new Button(this);
button1.setText("Spotify Streamer");
button2.setText("Scores App");
projectList.add(button1);
projectList.add(button2);
ArrayAdapter<Button> adapter =
new ArrayAdapter<Button>(this,R.layout.element_listview_layout,
R.id.list_item_string,projectList);
ListView listView = (ListView)findViewById(R.id.buttonListView);
listView.setAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/list_item_string"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:paddingLeft="8dp"
android:textSize="18sp"
android:textStyle="bold"
android:text=""/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/projectButton"
android:text="Hello world!"
android:layout_alignTop="@+id/list_item_string"
android:layout_centerHorizontal="true" />
</RelativeLayout>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.madelenko.showcase.MainActivityFragment"
tools:showIn="@layout/activity_main">
<ListView
android:layout_width="wrap_content"
android:layout_height="401dp"
android:id="@+id/buttonListView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_gravity="center" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="My nanodegree apps!"
android:id="@+id/textView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal|top" />
</FrameLayout>
public class ListViewDemo extends ListActivity {
private static final String[] items={"Spotify Streamer", "Scores App"};
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setListAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
items));
}
}
最后,我的listview如下所示:
package com.example.madelenko.showcase;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ArrayList<Button> projectList =
new ArrayList<Button>();
Button button1 = new Button(this);
Button button2 = new Button(this);
button1.setText("Spotify Streamer");
button2.setText("Scores App");
projectList.add(button1);
projectList.add(button2);
ArrayAdapter<Button> adapter =
new ArrayAdapter<Button>(this,R.layout.element_listview_layout,
R.id.list_item_string,projectList);
ListView listView = (ListView)findViewById(R.id.buttonListView);
listView.setAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/list_item_string"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:paddingLeft="8dp"
android:textSize="18sp"
android:textStyle="bold"
android:text=""/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/projectButton"
android:text="Hello world!"
android:layout_alignTop="@+id/list_item_string"
android:layout_centerHorizontal="true" />
</RelativeLayout>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.madelenko.showcase.MainActivityFragment"
tools:showIn="@layout/activity_main">
<ListView
android:layout_width="wrap_content"
android:layout_height="401dp"
android:id="@+id/buttonListView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_gravity="center" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="My nanodegree apps!"
android:id="@+id/textView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal|top" />
</FrameLayout>
public class ListViewDemo extends ListActivity {
private static final String[] items={"Spotify Streamer", "Scores App"};
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setListAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
items));
}
}
请对这个新手耐心点 ArrayAdapter
不是推荐的模式。适配器应该适应模型对象,无论这些对象是普通的(例如,ArrayAdapter
)还是更复杂的(例如,ArrayAdapter
)
因此,在这种情况下:
- 您正在创建一个
,但这些按钮将永远不会显示在屏幕上ArrayList
- 您正在为包含
和文本视图
的行扩展布局;这些按钮
小部件将显示在屏幕上按钮
- 创建
实例时,您正在告诉ArrayAdapter
将ArrayAdapter
按钮的
表示绑定到行中的字符串
(从字符串
调用ArrayList
到toString()
列表项字符串
)文本视图
ListView
行中看到按钮是非常罕见的,因为用户可以单击ListView
行本身
如果希望有一个包含两行字符串的列表视图
,可以执行以下操作:
package com.example.madelenko.showcase;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ArrayList<Button> projectList =
new ArrayList<Button>();
Button button1 = new Button(this);
Button button2 = new Button(this);
button1.setText("Spotify Streamer");
button2.setText("Scores App");
projectList.add(button1);
projectList.add(button2);
ArrayAdapter<Button> adapter =
new ArrayAdapter<Button>(this,R.layout.element_listview_layout,
R.id.list_item_string,projectList);
ListView listView = (ListView)findViewById(R.id.buttonListView);
listView.setAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/list_item_string"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:paddingLeft="8dp"
android:textSize="18sp"
android:textStyle="bold"
android:text=""/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/projectButton"
android:text="Hello world!"
android:layout_alignTop="@+id/list_item_string"
android:layout_centerHorizontal="true" />
</RelativeLayout>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.madelenko.showcase.MainActivityFragment"
tools:showIn="@layout/activity_main">
<ListView
android:layout_width="wrap_content"
android:layout_height="401dp"
android:id="@+id/buttonListView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_gravity="center" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="My nanodegree apps!"
android:id="@+id/textView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal|top" />
</FrameLayout>
public class ListViewDemo extends ListActivity {
private static final String[] items={"Spotify Streamer", "Scores App"};
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setListAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
items));
}
}
公共类ListViewDemo扩展ListActivity{
私有静态最终字符串[]项={“Spotify Streamer”,“Scores App”};
@凌驾
创建公共空间(捆绑冰柱){
超级冰柱;
setListAdapter(新阵列适配器)(此,
android.R.layout.simple\u list\u item\u 1,
(项目);;
}
}
非常感谢您的输入。我将使用相对布局并自行堆叠按钮。