简介

本文属于【Kotlin Jetpack 实战】系列文章。

这是我用 Java + MVC 写的一个 App，名字叫：KotlinJetpackInAction，它的功能只有一个：膜拜大神！

为了方便大家理解 Kotlin，Coroutines，Jetpack，Functional Programming，MMVM 这些新知识，这个 Demo 简单到了丧心病狂的程度。随着文章的更新，我会一步步用 Kotlin，Jetpack 将其重构，然后再往里面加一些新功能。

截图

Android 界无人不知，无人不晓的神级存在：JakeWharton

工程结构

MainActivity：用来膜拜大神

ImagePreviewActivity：用来瞻仰大神的头像

MainActivity 源码

public class MainActivity extends AppCompatActivity {
    public static final String TAG = "Main";
    public static final String EXTRA_PHOTO = "photo";

    StringRequest stringRequest;
    RequestQueue requestQueue;

    private ImageView image;
    private ImageView gif;
    private TextView username;
    private TextView company;
    private TextView website;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {
        image = findViewById(R.id.image);
        gif = findViewById(R.id.gif);
        username = findViewById(R.id.username);
        company = findViewById(R.id.company);
        website = findViewById(R.id.website);

        display(User.CACHE_RESPONSE);
        requestOnlineInfo();
    }

    private void requestOnlineInfo() {
        requestQueue = Volley.newRequestQueue(this);
        String url ="https://api.github.com/users/JakeWharton";
        stringRequest = new StringRequest(Request.Method.GET, url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        display(response);
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Toast.makeText(MainActivity.this, error.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });
        stringRequest.setTag(TAG);
        requestQueue.add(stringRequest);
    }

    private void display(@Nullable String response) {
        if (TextUtils.isEmpty(response)) { return; }

        Gson gson = new Gson();
        final User user = gson.fromJson(response, User.class);
        if (user != null){
            Glide.with(this).load("file:///android_asset/bless.gif").into(gif);
            Glide.with(this).load(user.getAvatar_url()).apply(RequestOptions.circleCropTransform()).into(image);
            this.username.setText(user.getName());
            this.company.setText(user.getCompany());
            this.website.setText(user.getBlog());

            image.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    gotoImagePreviewActivity(user);
                }
            });
        }
    }

    private void gotoImagePreviewActivity(User user) {
        Intent intent = new Intent(this, ImagePreviewActivity.class);
        intent.putExtra(EXTRA_PHOTO, user.getAvatar_url());
        startActivity(intent);
    }

    @Override
    protected void onStop () {
        super.onStop();
        if (requestQueue != null) {
            requestQueue.cancelAll(TAG);
        }
    }
}
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ImagePreviewActivity 源码

public class ImagePreviewActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_image_preview);

        Intent intent = getIntent();
        String url = intent.getStringExtra(MainActivity.EXTRA_PHOTO);
        if (!TextUtils.isEmpty(url)) {
            ImageView imageView = findViewById(R.id.imagePreview);
            Glide.with(this).load(url).into(imageView);
        }
    }
}
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结尾

我相信，即使是刚入门的小伙伴也能轻松看懂这个 Demo。

这也是本系列文章的不同之处，我会带着各位从这个简单 Demo 开始，一步步学习那些"高端"技术，最终把这个"简单"App变成"高端"App。

这是 Demo 的地址-->KotlinJetpackInAction

继续阅读请点击-->【Kotlin Jetpack 实战】传送门