使用对话框 —— Dialog
对话框就是一般的弹出窗口，主要用来提示用户，和用户交互。
创建Activity对话框
使用Activity模拟对话框。这个比较简单，主要是使用Activity自带的Dialog主题。
创建DialogActivity，并在AndroidManifest中注册。
改变DialogActivity的主题：
<activity android:theme="@android:style/Theme.Dialog" android:name="com.whathecode.usingdialog.DialogActivity" android:label="@string/title_activity_dialog" > </activity>
DialogActivity代码示例：
package com.whathecode.usingdialog; import android.app.Activity; import android.os.Bundle; import android.view.View; public class DialogActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_dialog); } //用来关闭这个Activity public void close(View view) { finish(); } }
DialogActivity布局文件：
<LinearLayout 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:padding="5dp" android:orientation="vertical" android:gravity="center_vertical|center_horizontal" tools:context=".DialogActivity" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="这是基于Activity的Dialog" /> <LinearLayout android:layout_marginTop="10dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal"> <Button android:id="@+id/confirm" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="确定" android:onClick="close"/> <Button android:id="@+id/cancel" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="取消" android:onClick="close"/> </LinearLayout> </LinearLayout>
MainActivity代码：
package com.whathecode.usingdialog; import android.content.Intent; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.view.View; public class MainActivity extends FragmentActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void openActivityDialog(View view) { Intent intent = new Intent(this, DialogActivity.class); startActivity(intent); } }
运行效果：
创建单选,多选和带进度条的对话框:
主要是使用AlertDialog类，首先通过创建AlertDialog类的实例，然后使用showDialog显示对话框。
showDialog方法的执行会引发onCreateDialog方法被调用
示例代码：
package com.whathecode.usingdialog; import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.app.ProgressDialog; import android.content.DialogInterface; import android.content.Intent; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.view.View; import android.widget.Toast; public class MainActivity extends Activity { private static final int SINGLE_CHOICE_DIALOG = 0; private static final int MULTI_CHOICE_DIALOG = 1; private static final int PROGRESS_DIALOG = 2; protected static final int MAX_PROGRESS = 30; private CharSequence items[] = new String[] { "apple", "google", "microsoft" }; private boolean checkedItems[] = new boolean[3]; private Handler progressHandler; private int progress; protected ProgressDialog progressDialog; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); progressHandler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(msg); if (progress >= MAX_PROGRESS) { progressDialog.dismiss(); //关闭progressDialog } else { progress++; //进度条加1 progressDialog.incrementProgressBy(1); //只要当前进度小于总进度，每个100毫秒发送一次消息 progressHandler.sendEmptyMessageDelayed(0, 100); } } }; } public void openActivityDialog(View view) { Intent intent = new Intent(this, DialogActivity.class); startActivity(intent); } //显示单选对话框 public void openSinglechoiceDialog(View view) { showDialog(SINGLE_CHOICE_DIALOG); } //显示多选对话框 public void openMultichoiceDialog(View view) { showDialog(MULTI_CHOICE_DIALOG); } //显示进度条对话框 public void openProgressDialog(View view) { showDialog(PROGRESS_DIALOG); progress = 0; progressDialog.setProgress(0); progressHandler.sendEmptyMessage(0); } @Override @Deprecated protected Dialog onCreateDialog(int id) { switch (id) { case SINGLE_CHOICE_DIALOG: return createSingleChoiceDialog(); case MULTI_CHOICE_DIALOG: return createMultichoiceDialog(); case PROGRESS_DIALOG: return createProgressDialog(); default: break; } return null; } /** * 创建单选对话框 * */ public Dialog createSingleChoiceDialog() { return new AlertDialog.Builder(this) .setTitle("单选对话框") //设置对话框标题 .setNegativeButton("取消", null) //设置取消按钮钮 .setPositiveButton("确定", null) //设置确定按 .setSingleChoiceItems(items, 0, //绑定数据 new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { Toast.makeText(getBaseContext(), items[which].toString(), Toast.LENGTH_SHORT).show(); } }).create(); } /** * 创建多选对话框 * */ public Dialog createMultichoiceDialog() { return new AlertDialog.Builder(this) .setTitle("多选对话框") //设置对话框标题 .setNegativeButton("取消", null) //设置取消按钮 .setPositiveButton("确定", null) //设置确定按钮 .setMultiChoiceItems(items, checkedItems, //绑定数据 new DialogInterface.OnMultiChoiceClickListener() { @Override public void onClick(DialogInterface dialog, int which, boolean isChecked) { Toast.makeText( getBaseContext(), isChecked ? items[which] + " check" : items[which] + " uncheck", Toast.LENGTH_SHORT).show(); } }).create(); } /** * 创建带进度条的对话框 * */ public Dialog createProgressDialog() { progressDialog = new ProgressDialog(this); progressDialog.setTitle("下载对话框"); progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); progressDialog.setMax(MAX_PROGRESS); progressDialog.setButton(DialogInterface.BUTTON_POSITIVE, "确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { } }); progressDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { } }); return progressDialog; } }
运行效果：
这里比较难理解还是ProgressDialog，因为它需要增加进度。这里我们通过向Activity线程发送消息，
从而能够使用progressDialog.incrementProgressBy(1)方法递增进度条。
