为什么要用构建者模式？什么时候用？
- 构建者模式，也叫Builder模式，一般用于构造一个复杂对象时使用，可以屏蔽构造的细节，Builder模式构造对象和多个参数分开，达到解耦的效果，并且能自由拓展。
怎样实现构建者模式
- 私有构造方法，构造只能由内部的Builder内部类的build方法创建。
- 内部类拷贝目标类的参数，提供set方法，并且每个set方法都返回builder实例自身，链式调用。
- 目标类提供一个私有支持Builder参数构造的构造方法（拷贝属性值到自身），给Builder的builder方法调用，传入自身。
- 构建时的处理，在builder中处理，不一定全是拷贝属性，例如一些默认值的处理、值越界的处理等。
Android中构建者模式的实现
- 对话框创建，AlertDialog
- 通知创建，Notification Builder
实例
Recorder录音配置Option
录音的前的一些配置，例如输出路径、文件前缀、文件后缀等属性。
使用
new RecorderOption.Builder().setOutputDirPath("xxx/yyy/zzz").setFilePrefix("voice").setFileSuffix(".aac").build()
- 实现
package com.hule.dashi.mediaplayer;
import android.text.TextUtils;
/**
* Package: com.hule.dashi.mediaplayer
* Create Date: 2019/2/19 4:04 PM
* @author: zihe
* Description: 录音配置
*/
public class RecorderOption {
private String outputDirPath;
private String filePrefix;
private String fileSuffix;
private RecorderOption() {
}
public RecorderOption(Builder builder) {
this.outputDirPath = builder.outputDirPath;
this.filePrefix = TextUtils.isEmpty(builder.filePrefix) ? "voice_" : builder.filePrefix;
this.fileSuffix = TextUtils.isEmpty(builder.fileSuffix) ? ".aac" : builder.fileSuffix;
}
public String getOutputDirPath() {
return outputDirPath;
}
public String getFilePrefix() {
return filePrefix;
}
public String getFileSuffix() {
return fileSuffix;
}
public static class Builder {
/**
* 输出目录路径
*/
private String outputDirPath;
/**
* 文件前缀
*/
private String filePrefix;
/**
* 文件后缀
*/
private String fileSuffix;
public Builder setOutputDirPath(String outputDirPath) {
this.outputDirPath = outputDirPath;
return this;
}
public Builder setFilePrefix(String filePrefix) {
this.filePrefix = filePrefix;
return this;
}
public Builder setFileSuffix(String fileSuffix) {
this.fileSuffix = fileSuffix;
return this;
}
public RecorderOption build() {
return new RecorderOption(this);
}
}
}
WebSocket配置
public class RxWebSocketBuilder {
/**
* 是否打印Log
*/
boolean mIsPrintLog;
/**
* Log代理对象
*/
Logger.LogDelegate mLogDelegate;
/**
* 支持外部传入OkHttpClient
*/
OkHttpClient mClient;
/**
* 支持SSL
*/
SSLSocketFactory mSslSocketFactory;
X509TrustManager mTrustManager;
/**
* 重连间隔时间
*/
long mReconnectInterval;
/**
* 重连间隔时间的单位
*/
TimeUnit mReconnectIntervalTimeUnit;
public RxWebSocketBuilder isPrintLog(boolean isPrintLog) {
this.mIsPrintLog = isPrintLog;
return this;
}
public RxWebSocketBuilder logger(Logger.LogDelegate logDelegate) {
Logger.setDelegate(logDelegate);
return this;
}
public RxWebSocketBuilder client(OkHttpClient client) {
this.mClient = client;
return this;
}
public RxWebSocketBuilder sslSocketFactory(SSLSocketFactory sslSocketFactory, X509TrustManager trustManager) {
this.mSslSocketFactory = sslSocketFactory;
this.mTrustManager = trustManager;
return this;
}
public RxWebSocketBuilder reconnectInterval(long reconnectInterval, TimeUnit reconnectIntervalTimeUnit) {
this.mReconnectInterval = reconnectInterval;
this.mReconnectIntervalTimeUnit = reconnectIntervalTimeUnit;
return this;
}
public RxWebSocket build() {
return new RxWebSocket(this);
}
}
图片压缩配置
- 使用
LinghitRichEditorImageCompressOption compressOption = LinghitRichEditorImageCompressOption
.Builder
.newBuilder()
.setBitmapConfig(Bitmap.Config.ARGB_4444)
//默认，多少张图片就多少个线程进行压缩
.setCompressTaskNum(files.size())
.setIsOrigin(false)
.build();
- 实现
public class LinghitRichEditorImageCompressOption {
private boolean isOrigin;
private Bitmap.Config mBitmapConfig;
private File mDiskDirectory;
private int mCompressTaskNum;
private Context mContext;
private String mTag;
public LinghitRichEditorImageCompressOption(Builder builder) {
this.isOrigin = builder.isOrigin;
this.mBitmapConfig = builder.mBitmapConfig == null ? Bitmap.Config.ARGB_8888 : builder.mBitmapConfig;
this.mDiskDirectory = builder.mDiskDirectory == null ? LinghitRichEditorUtil.getAppCacheDirFile() : builder.mDiskDirectory;
this.mCompressTaskNum = builder.mCompressTaskNum;
this.mContext = builder.mContext == null ? LinghitRichEditorUtil.getApplicationContext() : builder.mContext;
this.mTag = builder.mTag;
}
public boolean isOrigin() {
return isOrigin;
}
public Bitmap.Config getBitmapConfig() {
return mBitmapConfig;
}
public File getDiskDirectory() {
return mDiskDirectory;
}
public int getCompressTaskNum() {
return mCompressTaskNum;
}
public Context getContext() {
return mContext;
}
public String getTag() {
return mTag;
}
public static class Builder {
/**
* 是否是原图，这里一般用于图片，是否上传原图
* 如果为true，则不进行压缩，直接上传原文件
*/
private boolean isOrigin;
/**
* Bitmap的色彩格式
*/
private Bitmap.Config mBitmapConfig;
/**
* 压缩后的文件存放地址，一般都指定为App的Cache目录，如果需要放在别处，指定该参数
*/
private File mDiskDirectory;
/**
* 可同时进行压缩的任务数量
*/
private int mCompressTaskNum;
/**
* 这里最好传Activity，图片压缩会绑定Activity生命周期，如果在非Activity界面，无法传，则需要手动终止任务
*/
private Context mContext;
/**
* 本次任务的Tag，需要手动取消压缩任务时，使用该Tag去取消
*/
private String mTag;
private Builder() {
}
public static Builder newBuilder() {
return new Builder();
}
public Builder setIsOrigin(boolean isOrigin) {
this.isOrigin = isOrigin;
return this;
}
public Builder setBitmapConfig(Bitmap.Config config) {
this.mBitmapConfig = config;
return this;
}
public Builder setDiskDirectory(File diskDirectory) {
this.mDiskDirectory = diskDirectory;
return this;
}
public Builder setCompressTaskNum(int compressTaskNum) {
mCompressTaskNum = compressTaskNum;
return this;
}
public Builder setContext(Context context) {
mContext = context;
return this;
}
public Builder setTag(String tag) {
mTag = tag;
return this;
}
public LinghitRichEditorImageCompressOption build() {
return new LinghitRichEditorImageCompressOption(this);
}
}
}