<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical" ><TextViewandroid:id="@+id/text_view"android:layout_width="match_parent"android:layout_height="wrap_content"android:gravity="center"android:textSize="24sp"android:textColor="#00ff00"android:text="This is TextView" /></LinearLayout>

    <Button android:id="@+id/button"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="Button" />

public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button button = (Button) findViewById(R.id.button);button.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {}});        }
}

public class MainActivity extends Activity implements OnClickListener {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button button = (Button) findViewById(R.id.button);button.setOnclickListener(this);}public void onClick(View v) {
                 switch (v.getId()) {
                 case R.id.button:
                    //在此处添加逻辑
                    break;
                 default:
                    break;}}
}

<EditText android:id="@+id/edit_text"android:layout_width="match_parent"android:layout_height="wrap_content"android:hint="Type something here"android:maxLines="2" />

public class MainActivity extends Activity {private EditText editText;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);editText = (EditText) findViewById(R.id.edit_text);button.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String inputText = editText.getText().toString();Toast.makeText(MainActivity.this, inputText, Toast.LENGTH_SHORT).show();}});}
}

 <ImageView android:id="@+id/image_view"android:layout_width="wrap_content"android:layout_height="wrap_content"android:src="@drawable/ic_launcher" />

public class MainActivity extends Activity {private ImageView imageView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);imageView = (ImageView) findViewById(R.id.image_view);button.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {//在Button监听器中，调用ImageView的setImageResource()方法修改显示的图片。
            imageView.setImageResource(R.drawable.icon);}});}
}

<ProgressBarandroid:id="@+id/progress_bar" android:layout_width="match_parent"android:layout_height="wrap_content"style="?android:attr/progressBarStyleHorizontal"android:max="100" />"

public class MainActivity extends Activity {private ProgressBar progressBar;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);progressBar = (ProgressBar) findViewById(R.id.progress_bar);button.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {//设置进度条的可见性if (progressBar.getVisibility() == View.GONE){progressBar.setVisibility(View.VISIBLE);}else {progressBar.setVisibility(View.GONE);}int progress = progressBar.getProgress();progress = progress + 10;progressBar.setProgress(progress);}});}
}                

/*** AlertDialog可以在当前的界面弹出一个对话框，这个对话框是置顶于所有* 界面元素之上的，能够屏蔽掉其他控件的交互能力。*/             //首先通过AlertDialog.Builder创建出一个AlertDialog的实例。AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);//设置标题dialog.setTitle("This is Dialog");//设置内容dialog.setMessage("Something important");//设置是否可以取消dialog.setCancelable(false);//调用setPositiveButton()方法为对话框设置确定按钮的点击事件dialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {}});//调用setNegativeButton()方法为对话框设置取消按钮的点击事件dialog.setNegativeButton("Cancle", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {}});//调用show()方法将对话框显示出来
                dialog.show();

                /*** ProgressDialog和AlertDialog类似，都是在界面中显示一个对话框。* 不同的是，ProgressDialog会在对话框中显示一个进度条，一般表示：* 当前的操作比较耗时，让用户耐心等待。*///首先构建出一个ProgressDialog对象。ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);//设置对话框的标题progressDialog.setTitle("This is ProgressDialog");//设置内容消息progressDialog.setMessage("Loading...");//设置可否取消,如果在setCancelable()中传入了false，表示ProgressDialog不能通过Back键取消，//当数据加载完成后必须要调用ProgressDialog的dismiss()方法来关闭对话框。progressDialog.setCancelable(true);//调用show()方法将对话框显示出来progressDialog.show();