1.TextView（文本框）
<TextView
android:id="@+id/text_view"
android:layout_width="match_parent" <!--和父布局大小一致-->
android:layout_height="wrap_content"<!--刚好包住里面的内容-->
android:gravity="center" <!--居中-->
android:text="This is TextView"
android:textColor="#00ff00"
android:textSize="24sp" />
2.Button（按钮）
<Button
android:id="@+id/button"
android:text="Button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAllCaps="false"/>
注册监听器
方法一：匿名类
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//内容
}
});
}
}
方法二：使用实现接口
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(this);
}
@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button:
//添加逻辑
break;
default:
break;
}
}
}
3.EditText
允许用户在控件里输入和编辑内容，并可以在程序中对这些内容进行处理
<EditText
android:id="@+id/edit_text"
android:hint="Type something there"<!--提示性文本-->
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:maxLines="2"<!--最大行数为2行-->
/>
按一下按钮，弹出提示文本
public class MainActivity extends AppCompatActivity implements View.OnClickListener //entends类，implement接口
{
private EditText editText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
editText = (EditText) findViewById(R.id.edit_text);
button.setOnClickListener(this);
}
@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button:
String inputText = editText.getText().toString(); //转换成字符串
Toast.makeText(MainActivity.this,inputText,Toast.LENGTH_SHORT).show();//注意toast的用法
break;
default:
break;
}
}
}
4.ImageView（图片）
<ImageView
android:id="@+id/image_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/img_1"/> <!--指定一张图片-->
按一下按钮换图片
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private ImageView imageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
imageView = (ImageView) findViewById(R.id.image_view);
button.setOnClickListener(this);
}
@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button:
imageView.setImageResource(R.drawable.img_2);
break;
default:
break;
}
}
}
5.ProgressBar（进度条）
<ProgressBar
android:id="@+id/progress_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
按一下按钮，改变进度条状态
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private ProgressBar progressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
progressBar = (ProgressBar)findViewById(R.id.progress_bar);
button.setOnClickListener(this);
}
@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button:
if(progressBar.getVisibility() == View.GONE){
progressBar.setVisibility(View.VISIBLE);
}else{
progressBar.setVisibility(View.GONE);
}
break;
default:
break;
}
}
}
控件的可见属性（使用android:visibility指定）：
visible：可见
invisible：不可见，但仍占据着屏幕的空间（透明）
gone：不可见，不占据屏幕空间
水平进度条
<ProgressBar
android:id="@+id/progress_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
style="?android:attr/progressBarStyleHorizontal"
android:max="100"/>
每按一次按钮，进度条加10
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private ProgressBar progressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
progressBar = (ProgressBar)findViewById(R.id.progress_bar);
button.setOnClickListener(this);
}
@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button:
int progress = progressBar.getProgress();
progress = progress + 10;
progressBar.setProgress(progress);
break;
default:
break;
}
}
}
6.AlertDialog（弹出对话框）
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private ProgressBar progressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
progressBar = (ProgressBar)findViewById(R.id.progress_bar);
button.setOnClickListener(this);
}
@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button:
AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
dialog.setTitle("This is Dialog"); //对话框标题
dialog.setMessage("Something important"); //对话框内容
dialog.setCancelable(false);//可否用back键关闭对话框
dialog.setPositiveButton("OK", new DialogInterface.OnClickListener() { //设置确认按钮点击事件
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { //设置取消按钮点击事件
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
dialog.show(); //显示对话框
break;
default:
break;
}
}
}
7.ProgressDialog（弹出带进度条的对话框）
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private ProgressBar progressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
progressBar = (ProgressBar)findViewById(R.id.progress_bar);
button.setOnClickListener(this);
}
@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button:
ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);
progressDialog.setTitle("This is a ProgressDialog");
progressDialog.setMessage("Loading...");
progressDialog.setCancelable(true);
progressDialog.show();
break;
default:
break;
}
}
}