Android--序列化/数据存入、读出SD卡

序列化

内外存储写对象，需要写对象，在内存中传递对象，A activity 传入b activity中需要序列化。

序列化两种：serializable、Parcelable

支持可序列化：

对象读写文件推荐使用：serializable

在JAVA中建议使用Parcelable

例题：将数据传入SD卡中，启动就会读取



本题有两种方法：1.传入字符串：读取时根据分割字符读取

2.传入一个实体类

本题中使用第一种，在此给出第二种的方法

//传进去一个Object类
ok.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Message message=new Message();
message.setTitle(c1.isChecked());
message.setChajian(c3.isChecked());
message.setInformation(c2.isChecked());
message.setRead(c4.isChecked());
message.setCollection(c5.isChecked());
message.setCollection(c6.isChecked());
message.setSize(tv3.getText().toString());
String statu=Environment.getExternalStorageState();
if (!statu.equals(Environment.MEDIA_MOUNTED)){
Toast.makeText(SettingSDActivity.this,"SD卡未就绪",Toast.LENGTH_SHORT).show();
return ;
}

File root=Environment.getExternalStorageDirectory();
FileOutputStream fos=null;
ObjectOutputStream oos=null;
try {
fos=new FileOutputStream(root+"/settings.txt");
try {
oos=new ObjectOutputStream(fos);
oos.writeObject(message);
} catch (IOException e) {
e.printStackTrace();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}finally {
if (fos != null) {
try {
fos.close();
fos.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
});
}

下面是实体对象的class文件

此处继承了Serializable 接口，实现序列化

public class Message implements Serializable {
private Boolean title;
private String size;
private Boolean information;
private Boolean chajian;
private Boolean read;
private Boolean collection;
private Boolean top;

public Message(Boolean title, String size, Boolean information, Boolean chajian, Boolean read, Boolean collection, Boolean top) {
this.title = title;
this.size = size;
this.information = information;
this.chajian = chajian;
this.read = read;
this.collection = collection;
this.top = top;
}

public Boolean getTitle() {
return title;
}

public void setTitle(Boolean title) {
this.title = title;
}

public String getSize() {
return size;
}

public void setSize(String size) {
this.size = size;
}

public Boolean getInformation() {
return information;
}

public void setInformation(Boolean information) {
this.information = information;
}

public Boolean getChajian() {
return chajian;
}

public void setChajian(Boolean chajian) {
this.chajian = chajian;
}

public Boolean getRead() {
return read;
}

public void setRead(Boolean read) {
this.read = read;
}

public Boolean getCollection() {
return collection;
}

public void setCollection(Boolean collection) {
this.collection = collection;
}

public Boolean getTop() {
return top;
}

public void setTop(Boolean top) {
this.top = top;
}

public Message() {

}

}

下面为第一种方法代码：需要注意的是开始没有文件，会报错，需要加如判断。

public class SettingSDActivity extends AppCompatActivity {
private CheckBox c1,c2,c3,c4,c5,c6;
private TextView tv3,ok;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_setting_sd);
c1=(CheckBox)findViewById(R.id.c1);
c2=(CheckBox)findViewById(R.id.c2);
c3=(CheckBox)findViewById(R.id.c3);
c4=(CheckBox)findViewById(R.id.c4);
c5=(CheckBox)findViewById(R.id.c5);
c6=(CheckBox)findViewById(R.id.c6);
tv3=(TextView)findViewById(R.id.tv3);
ok=(TextView)findViewById(R.id.ok);
tv3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
AlertDialog.Builder builder=new AlertDialog.Builder(SettingSDActivity.this);
builder.setTitle("字体大小请选择");
builder.setIcon(R.mipmap.ic_launcher);
final String[] items={"大","中","小"};
// builder.setMultiChoiceItems()多选
builder.setSingleChoiceItems(items, 1, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int i) {
Toast.makeText(getBaseContext(), items[i].toString(), Toast.LENGTH_SHORT).show();
tv3.setText(items[i].toString());
dialog.dismiss();
}
});
builder.setCancelable(false);
AlertDialog alertDialog=builder.create();
alertDialog.show();
}
});

ok.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
saveFile();
}
});

//保存到SD卡上，
public  void saveFile(){
FileOutputStream fos=null;
//获取SD卡状态
String state= Environment.getExternalStorageState();
//判断SD卡是否就绪
if(!state.equals(Environment.MEDIA_MOUNTED)){
Toast.makeText(this, "请检查SD卡", Toast.LENGTH_SHORT).show();
return;
}
//取得SD卡根目录
File file= Environment.getExternalStorageDirectory();
try {
Log.d("=====SD卡根目录：", file.getCanonicalPath().toString());
//输出流的构造参数1：可以是File对象，也可以是文件路径
//输出流的构造参数2：默认为fasle=>覆盖内容：true=>追加内容
//            File myFile=new File(file.getCanonicalPath()+"/sd.txt");
//            fos=new FileOutputStream(myFile);
//加true追加模式
//文件位置
fos=new FileOutputStream(file.getCanonicalPath()+"/sd.txt");
String  str=content();
fos.write(str.getBytes());
Toast.makeText(this,"保存成功",Toast.LENGTH_SHORT).show();
} catch (IOException e) {
e.printStackTrace();
}finally {
if (fos!=null){
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public String content(){
String a,b,c,d,e,f,g,h;
if(c1.isChecked()){
a="check";
}else{
a="uncheck";
}
if(c2.isChecked()){
b="check";
}else{
b="uncheck";
}
if(c3.isChecked()){
c="check";
}else{
c="uncheck";
}
if(c4.isChecked()){
d="check";
}else{
d="uncheck";
}
if(c5.isChecked()){
e="check";
}else{
e="uncheck";
}
if(c6.isChecked()){
f="check";
}else{
f="uncheck";
}
g=tv3.getText().toString();
h=a+"#"+g+"#"+b+"#"+c+"#"+d+"#"+e+"#"+f;
return h;
}

//读取文件
public String  readFile(){
BufferedReader reader=null;
FileInputStream fis=null;
StringBuilder sbd=new StringBuilder();
String statu=Environment.getExternalStorageState();
if (!statu.equals(Environment.MEDIA_MOUNTED)){

Toast.makeText(this,"SD卡未就绪",Toast.LENGTH_SHORT).show();
return  "";
}
//拿到SD卡根目录
File root=Environment.getExternalStorageDirectory();
try {
fis=new FileInputStream(root+"/sd.txt");
reader= new BufferedReader(new InputStreamReader(fis));
String row="";
try {
while ((row=reader.readLine())!=null){

sbd.append(row);
}
} catch (IOException e) {
e.printStackTrace();
}
} catch (FileNotFoundException e) {
Toast.makeText(this,"文件不存在",Toast.LENGTH_SHORT).show();
e.printStackTrace();
}finally {
if (reader!=null){
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return  sbd.toString();
}

//一开始就读取
@Override
protected void onStart() {
super.onStart();
String my = readFile();
if(my != ""){
String k[] = my.split("#");
if (k[0].equals("check")) {
c1.setChecked(true);
} else {
c1.setChecked(false);
}
tv3.setText(k[1]);
if (k[2].equals("check")) {
c2.setChecked(true);
} else {
c2.setChecked(false);
}
if (k[3].equals("check")) {
c3.setChecked(true);
} else {
c3.setChecked(false);
}
if (k[4].equals("check")) {
c4.setChecked(true);
} else {
c4.setChecked(false);
}
if (k[5].equals("check")) {
c5.setChecked(true);
} else {
c5.setChecked(false);
}
if (k[6].equals("check")) {
c6.setChecked(true);
} else {
c6.setChecked(false);
}
}
}
}

接下来是布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">

<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal">

</LinearLayout>

<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:layout_width="280dp"
android:layout_height="wrap_content"
android:text="设置"
android:textSize="25sp"
android:gravity="center"
/>
<TextView
android:id="@+id/ok"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="提交"
android:textSize="25sp"
/>

</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="列表显示摘要"
android:textSize="25sp"

/>
<CheckBox
android:id="@+id/c1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25sp"
android:layout_marginLeft="150dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
android:id="@+id/LL1"
>
<TextView
android:id="@+id/tv2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="字体大小"
android:textSize="25sp"
/>
<TextView
android:id="@+id/tv3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="中 >"
android:textSize="25sp"
android:layout_marginLeft="205dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:id="@+id/tv4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="列表页评论"
android:textSize="25sp"
/>
<TextView
android:id="@+id/tv5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="不限 >"
android:textSize="25sp"
android:layout_marginLeft="153dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:id="@+id/tv6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="2G/3G网络流量"
android:textSize="25sp"
/>
<TextView
android:id="@+id/tv7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="较省流量（普通下载）>"
android:textSize="15sp"
android:layout_marginLeft="15dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:id="@+id/tv8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="清理缓存"
android:textSize="25sp"
/>
<TextView
android:id="@+id/tv9"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="当前缓存：2.48MB>"
android:textSize="20sp"
android:layout_marginLeft="70dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:id="@+id/tv10"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="推送通知"
android:textSize="25sp"
/>
<CheckBox
android:id="@+id/c2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="200dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:id="@+id/tv11"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="互动插件"
android:textSize="25sp"
/>
<CheckBox
android:id="@+id/c3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="200dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:id="@+id/tv12"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="自动优化阅读"
android:textSize="25sp"
/>

<CheckBox
android:id="@+id/c4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="152dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:id="@+id/tv13"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="收藏时转发"
android:textSize="25sp"
/>
<CheckBox
android:id="@+id/c5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"

android:layout_marginLeft="175dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
>
<TextView
android:id="@+id/tv14"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="顶踩时转发"
android:textSize="25sp"
/>
<CheckBox
android:id="@+id/c6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="175dp"
/>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#a9a8a8"
></View>

</LinearLayout>

</ScrollView>
</LinearLayout>

实现效果如下：