Video URL: http://www.imooc.com/learn/756
Successfully entered the pit Android Studio
1. Implement the main interface layout
2.json data acquisition and parsing
3. Introduction to MPAndroidChart
1. Implement the main interface layout
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
android:id="@+id/vp_main"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>
</RelativeLayout>
The first problem encountered:
android.support.v4.view.ViewPager
what is it?
After searching, it is known that it is used to display the interface of left and right sliding.
The following blog link explains how to use ViewPager in detail, as well as some good code exercises.
http://blog.csdn.net/wangjinyu501/article/details/8169924
MainActivity.java
public class MainActivity extends AppCompatActivity {
private ViewPager vpMain;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate (savedInstanceState);
setContentView(R.layout.activity_main);
vpMain= (ViewPager) findViewById(R.id.vp_main);
initView();
}
private void initView() {
vpMain.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {
@Override
public Fragment getItem(int position) {
return PieFragment.newInstance(position+"");
}
@Override
public int getCount() {
return 4;//Return 4 means there are 4 interfaces
}
});
}
}
PieFragment.java
public class PieFragment extends Fragment {
private static final String DATA_KEY ="piefragment_data_key";
private String mData;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate (savedInstanceState);
Bundle arguments = getArguments();
if (arguments != null) {
mData=arguments.getString(DATA_KEY);
}
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
TextView textView=new TextView(getContext());
textView.setText(mData);
return textView;
}
public static PieFragment newInstance(String data) {
Bundle args = new Bundle();
args.putString(DATA_KEY,data);
PieFragment fragment = new PieFragment();
fragment.setArguments(args);
return fragment;
}
}
These codes are really difficult for me at present, and I should understand them when I encounter them more in the future.
Hey, the compiler reported an error unfortunately, but I felt that my code was fine. After many setbacks, I finally found out that the Fragment package was referenced wrongly and should be referenced
import android.support.v4.app.Fragment;The program runs successfully to the mobile phone, and the interface of android studio is very beautiful.
2.json data acquisition and parsing
Obtain:
MainActivity.java
private String mJson="[{\"date\":\"2016年5月\",\"obj\":
[{\"title\":\"外卖\",\"value\":34}," +
"{\"title\":\"娱乐\",\"value\":21},
{\"title\":\"其他\",\"value\":45}]}," +
"{\"date\":\"2016年6月\",\"obj\":
[{\"title\":\"外卖\",\"value\":32}," +
"{\"title\":\"娱乐\",\"value\":22},
{\"title\":\"其他\",\"value\":42}]}," +
"{\"date\":\"2016年7月\",\"obj\":
[{\"title\":\"外卖\",\"value\":34}," +
"{\"title\":\"娱乐\",\"value\":123},
{\"title\":\"其他\",\"value\":24}]}," +
"{\"date\":\"2016年8月\",\"obj\":
[{\"title\":\"外卖\",\"value\":145}," +
"{\"title\":\"娱乐\",\"value\":123},
{\"title\":\"其他\",\"value\":124}]}]";
Parse:
Download gson-2.2.4.jar, copy and paste it into the libs folder, right-click gson-2.2.4.jar, click Add As Library and select OK.
New MonthBean.java
{"date":"2016年5月","obj":[{"title":"外卖","value":34}
*/
public class MonthBean {
public String date;
public ArrayList<PieBean> obj;
@Override
public String toString() {
return "MonthBean{" +
"date='" + date + '\'' +
", obj=" + obj.toString() +
'}';
}
class PieBean {
public String title;
public int value;
@Override
public String toString() {
return "PieBean{" +
"title='" + title + '\'' +
", value=" + value +
'}';
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public int getValue() {
return value;
}
public void setValue(int value) {
this.value = value;
}
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public ArrayList<PieBean> getObj() {
return obj;
}
public void setObj(ArrayList<PieBean> obj) {
this.obj = obj;
}
}
get set toString shortcut right click and select Generate.
MainActivity.java
public class MainActivity extends AppCompatActivity {
private ArrayList<MonthBean> mData;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate (savedInstanceState);
setContentView(R.layout.activity_main);
initData ();
}
private void initData() {
Gson gson = new Gson ();
mData=gson.fromJson(mJson,new TypeToken<ArrayList<MonthBean>>(){}.getType());
}
private void initView() {
vpMain.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {
@Override
public Fragment getItem(int position) {
return PieFragment.newInstance(mData.get(position).toString());
}
@Override
public int getCount() {
return mData.size();
}
});
}
}
run successfully
3. Introduction to MPAndroidChart
https://github.com/PhilJay/MPAndroidChart
Usage: In Android Stidio
Add the following to your project level build.gradle:
allprojects {
repositories {
jcenter ()
maven { url "https://jitpack.io" }
}
}
Add this to your app build.gradle
dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:24.2.1'
testCompile 'junit:junit:4.12'
compile files('libs/gson-2.2.4.jar')
compile 'com.github.PhilJay: MPAndroidChart: v3.0.2'
}
MPAndroidChart feels very good, and should do more of the above practice in the future.
There is also a shortcut key to remember alt+ctrl+l to organize the code.