React Native:用 java 在 AsyncStorage 中编写

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问题描述

所以我在 java 端有这个来自 Intent 的文本，我想将其保存到 AsyncStorage 以便能够通过 React 访问它之后.

So I have this text on the java-side that arrives from an Intent, which I'd like to save to AsyncStorage to being able to access it through React afterwards.

我有机会做到这一点吗?

Any chance I can achieve this?

我有:

package com.myapp;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.content.Intent;


import com.facebook.react.LifecycleState;
import com.facebook.react.ReactInstanceManager;
import com.facebook.react.ReactRootView;
import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
import com.facebook.react.shell.MainReactPackage;
import com.facebook.soloader.SoLoader;

public class MainActivity extends Activity implements DefaultHardwareBackBtnHandler {

    private ReactInstanceManager mReactInstanceManager;
    private ReactRootView mReactRootView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mReactRootView = new ReactRootView(this);

        mReactInstanceManager = ReactInstanceManager.builder()
                .setApplication(getApplication())
                .setBundleAssetName("index.android.bundle")
                .setJSMainModuleName("index.android")
                .addPackage(new MainReactPackage())
                .setUseDeveloperSupport(BuildConfig.DEBUG)
                .setInitialLifecycleState(LifecycleState.RESUMED)
                .build();

        mReactRootView.startReactApplication(mReactInstanceManager, "BrowseItLater", null);

        setContentView(mReactRootView);

        // This code is from http://developer.android.com/training/sharing/receive.html
        Intent intent = getIntent();
        String action = intent.getAction();
        String type = intent.getType();
        if (Intent.ACTION_SEND.equals(action) && type != null) {
            handleSendText(intent);
        }
    }

    void handleSendText(Intent intent) {
        String sharedText = intent.getStringExtra(Intent.EXTRA_TEXT);
        if (sharedText != null) {
            // How can I handle this ????
        }
    }
// ...
}

或者有没有其他的办法让MainActivity.java和JS通信?

Or is there any other solution to make MainActivity.java communicate with JS?

推荐答案

经过一番折腾我终于找到了解决方案.它不使用 AsyncStorage，因为我在源代码中读到 AsyncStorage 实际上可能位于不同的位置(SQLite 或其他东西)，具体取决于手机.复制这个逻辑会很脏.

After quite some fight I finally found a solution. It doesn't use AsyncStorage as I read in the source code AsyncStorage could actually be located differently (SQLite, or something else) depending on the phone. Would be dirty to duplicate this logic.

相反，我创建了一个像文档建议的模块并将 inputText 作为参数传递给 MainActivity.java 中的 .addPackage(new EphemeralStoragePackage(inputText)) 调用.

Instead, I created a module like the doc suggests and passed the inputText as an argument to the .addPackage(new EphemeralStoragePackage(inputText)) call in MainActivity.java.

该模块向 JS 世界公开了一个方法 readOnceAsync，我可以稍后调用它:

The module exposes a method readOnceAsync to the JS world, which I can later call with:

NativeModules.EphemeralStorage.readOnceAsync((text :string) => {
  if (text.length) {
    this._addValue(text); // this method is in charge of storing in AsyncStorage
  }
})

详情如下:

Here's the detail:

// android/app/src/main/java/com/appname/modules/ephemeralstorage/EphemeralStorageModule.java

package com.browseitlater.modules.ephemeralstorage;

import com.facebook.react.bridge.NativeModule;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.bridge.ReactMethod;
import com.facebook.react.bridge.Callback;

import java.util.Map;

public class EphemeralStorageModule extends ReactContextBaseJavaModule {
  private String inputText;

  public EphemeralStorageModule(ReactApplicationContext reactContext, String _inputText) {
    super(reactContext);
    this.inputText = _inputText;
  }

  @Override
  public String getName() {
    return "EphemeralStorage";
  }

  public String getInputText() {
    return inputText;
  }

  @ReactMethod
  public void readOnceAsync(Callback successCallback) {
    successCallback.invoke(getInputText());
    this.inputText = null;
  }

}

还有

// android/app/src/main/java/com/appname/modules/ephemeralstorage/EphemeralStoragePackage.java
package com.browseitlater.modules.ephemeralstorage;

import android.app.Activity;

import java.util.*;

import com.facebook.react.ReactPackage;
import com.facebook.react.bridge.JavaScriptModule;
import com.facebook.react.bridge.NativeModule;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.uimanager.ViewManager;


public class EphemeralStoragePackage implements ReactPackage {
  private String inputText;

  public EphemeralStoragePackage(String _inputText) {
    super();
    this.inputText = _inputText;
  }

  @Override
  public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
    List<NativeModule> modules = new ArrayList<>();
    modules.add(new EphemeralStorageModule(reactContext, getInputText()));
    return modules;
  }

  @Override
  public List<Class<? extends JavaScriptModule>> createJSModules() {
    return Collections.emptyList();
  }

  @Override
  public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
    return Collections.emptyList();
  }

  public String getInputText() {
    return inputText;
  }

}

最后在 MainActivity.java 中，我的 onCreate 方法看起来像:

Finally in MainActivity.java, my onCreate method looks like:

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mReactRootView = new ReactRootView(this);

    Intent intent = getIntent();
    String action = intent.getAction();
    String type = intent.getType();
    String inputText = intent.getStringExtra(Intent.EXTRA_TEXT);

    mReactInstanceManager = ReactInstanceManager.builder()
      .setApplication(getApplication())
      .setBundleAssetName("index.android.bundle")
      .setJSMainModuleName("index.android")
      .addPackage(new MainReactPackage())
      .addPackage(new EphemeralStoragePackage(inputText))
      .setUseDeveloperSupport(BuildConfig.DEBUG)
      .setInitialLifecycleState(LifecycleState.RESUMED)
      .build();

    mReactRootView.startReactApplication(mReactInstanceManager, "BrowseItLater", null);

    setContentView(mReactRootView);

  }

这篇关于React Native:用 java 在 AsyncStorage 中编写的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！